When a film franchise lasts for more than five decades, it’s bound to gather a few unrealized projects along the way, and the James Bond series is no exception. Over the years, actors as varied as Michael Caine, Dick Van Dyke, Clint Eastwood and Liam Neeson have come close to playing the suave Agent 007, leaving fans to speculate on the vastly different directions the series might have gone in had they been cast.

Similarly, rejected theme songs from Johnny Cash, Blondie and Alice Cooper, along with discarded titles like “From a View to a Kill” (shortened by one word upon release) and “Licence Revoked” (changed when test audiences responded poorly to it) suggest an alternate history for the cinematic super spy. Even more curious, however, are the following four films which, to varying degrees, came close to actual production.

Alfred Hitchcock’s “Thunderball”

While A-list directors like Steven Spielberg and Quentin Tarantino have flirted with the idea of helming a James Bond film, perhaps none was better suited to the material than Alfred Hitchcock, who was approached in 1959 to direct the very first entry in the series.

“It was Ian Fleming’s idea to contact Hitchcock,” said Chris Wright, co-host of the popular James Bond Radio podcast. “He sent a telegram to Hitchcock through a mutual friend, asking if he’d be interested in directing Bond’s movie debut.”

That project was an early version of “Thunderball.”

Fleming’s telegram described the script’s basic plot, which centered on the Mafia stealing an atomic bomb to blackmail England. Sadly, the two men never met in person to discuss it.

“It’s unclear whether Hitchcock read the ‘Thunderball’ script that Fleming was touting,” said Tom Sears, co-host of the James Bond Radio podcast. “Though he may have considered the offer, he didn’t want to make another spy thriller so soon after ‘North by Northwest.’”

But who would have played Bond if Hitchcock’s “Thunderball” had moved forward?

“Richard Burton was mentioned as a possible 007 at the time,” Sears said. “But Fleming would’ve been happy with Jimmy Stewart if it meant that Hitchcock was behind the camera.”

Instead, the director began work on “Psycho,” while Fleming retooled the screenplay into his eighth full-length Bond novel.

“Had Hitchcock directed, we would’ve seen a very different Bond than the one we first met in ‘Dr. No,’” Wright said. “The character would have been a lot closer to Fleming’s literary version and the one-liners would probably have been absent as well.”

George Lazenby in “Diamonds Are Forever”

To many fans, 1969’s “On Her Majesty’s Secret Service” remains the series’ high-water mark in terms of adventure, romance and style. But Australian model-turned-actor George Lazenby threw Eon Productions into turmoil when, prior to the film’s release, he announced that he wouldn’t be returning as Bond for a sequel.

This presented a major problem since the follow-up, an adaptation of the novel “Diamonds Are Forever,” had already been written by longtime Bond screenwriter Richard Maibaum. Several treatments and a script were completed while the film was still in post-production.

“The initial treatments were very much revenge-themed,” said Bond historian Charles Helfenstein, author of “The Making of On Her Majesty’s Secret Service” and “The Making of The Living Daylights.”

With “On Her Majesty’s” director Peter Hunt choosing to sit this one out, “Goldfinger” helmer Guy Hamilton was tapped to lead the new production.

“It would have been a true sequel,” Helfenstein said. “Secondary characters like Irma Bunt and Marc Ange Draco would have returned, and it even featured a scene where Bond mourns his murdered wife while Louis Armstrong’s familiar theme plays in the background.”

Unfortunately, Lazenby’s sudden departure required a complete rewrite.

“The fact that we never got to see Lazenby brutally extract revenge against Blofeld for murdering his bride is quite a missed opportunity,” Helfenstein added.

But would a dark and violent version of “Diamonds Are Forever” have worked at that point in the franchise?

“Hard-core Bond fans would have loved it,” Helfenstein said. “But Maibaum’s treatments about a revenge-obsessed Bond didn’t impress Cubby Broccoli and Harry Saltzman.”

Ultimately, Eon’s decision to revamp the story proved to be a wise move. When it was released on December 14, the campier version of “Diamonds are Forever,” starring a visibly disinterested Sean Connery, became the fifth highest grossing film of 1971 at the domestic box office, and number one worldwide, earning a whopping $116 million.

Most importantly, it represented a creative turning point in the series. “The lighter version ushered in a more humorous Bond,” Helfenstein said. “It was the perfect gateway to the very successful Roger Moore era.”

Kevin McClory’s “Warhead”

Ian Fleming had no idea of the legal mess he was getting into when he collaborated with filmmaker Kevin McClory on an original Bond script that would later serve as the basis for the novel “Thunderball.” When their partnership ended, McClory sued the author and won the film rights to the story. This resulted in several aborted attempts by McClory to bring his own version to the screen.

“In 1976, McClory tried to make a movie titled ‘James Bond of the Secret Service,’” said podcaster Chris Wright. “The first draft shared some remarkable similarities with Eon’s ‘The Spy Who Loved Me,’ including an underwater base and an invulnerable henchman.”

Sean Connery himself contributed material to the script, which was soon reworked into a new project called “Warhead.”

“‘Warhead’ would have featured SPECTRE using The Statue of Liberty as their base, and included robot sharks armed with explosives swimming around the New York sewer system!” said Wright.

Described by Hollywood insiders as “Star Wars underwater,” the outrageous project fell apart when Connery, frustrated by McClory’s continued legal wranglings, pulled out.

Eventually, McClory and Connery worked together on the 1983 “Thunderball” remake “Never Say Never Again,” but that didn’t stop the filmmaker from seeking to produce yet another version of the same material several years later. Re-titled “Warhead 2000,” the script managed to attract the attention of Sony Pictures, which showed interest in developing it.

“But the whole thing was quickly scrapped after McClory’s ownership rights to the original ‘Thunderball’ script were questioned in court,” said James Bond Radio’s Tom Sears. “Which makes this version one of the ultimate ‘What If’ Bond movies.”

Halle Berry’s “Jinx” Spin-Off

The concept of a female-driven spin-off series originated in 1997 with the Bond thriller “Tomorrow Never Dies.” Malaysian actress Michelle Yeoh, whose charisma and fighting skills made her a superstar on the Hong Kong action film circuit, starred as Wai Lin, a master spy in China’s elite Secret Service. The character proved so popular that MGM briefly considered developing a solo film around her. When that didn’t pan out, producers decided to bring her back for the 2002 Bond film “Die Another Day.” Unfortunately, scheduling conflicts prevented Yeoh’s return.

Word of a spin-off series involving Halle Berry’s character Jinx from “Die Another Day” began circulating while the film was still in theaters. Rumors hinted at a planned winter release in 2004.

“Bond screenwriters Neal Purvis and Robert Wade were hired to write the script and, though it was never officially announced, Stephen Frears was on board to direct,” said Chris Wright. “But in late October of the following year, MGM pulled the plug.”

Reasons for its cancellation remain unclear.

When news first broke, a spokesperson for Eon producers Barbara Broccoli and Michael G. Wilson claimed that “creative differences” were involved. But Variety reported that MGM’s decision to nix the film took the Eon team by surprise. In any event, no apparent effort was made to set the project up at another studio.

Perhaps Jinx simply wasn’t dynamic enough to build a new franchise around? The character, a skilled NSA operative with a mean left hook, remains more memorable for her stylish orange bikini and Ursula Andress-like entrance than for her originality or depth.

“Not a lot is known about the script itself,” said Tom Sears. “But Purvis and Wade have suggested that their idea was to involve Jinx in a story that would’ve been a lot less excessive than ‘Die Another Day.’”