Summit Entertainment and Lionsgate may be getting closer to a walk down the aisle — possibly as early as this week — though it’s far from a done deal.

The mini-majors have been negotiating exclusively with each other in recent days, according to sources with knowledge of the situation. But some cautioned that merger talks could take several more weeks to conclude and there is no certainty an agreement will be reached given the complexity of the transaction and the possibility of a sweetened offer from Miramax owner Colony Capital.

The question of leadership has been key in the talks. If the deal goes through, it’s understood that Lionsgate CEO and co-chair Jon Feltheimer and vice chair Michael Burns would head the merged entity, with Summit toppers Rob Friedman and Patrick Wachsberger in charge of the motion picture operations.

The companies had no comment Sunday.

Colony Capital, which had been in talks with Summit in recent months, could get back into the bidding. Reps for Colony also had no comment over the weekend after word spread that Lionsgate was closing in on a deal.

People familiar with the situation have indicated that Lionsgate’s bid for Summit amounts to about $400 million — nearly all cash plus a small amount of stock. A large chunk of Summit’s debt — $200 million-$300 million — will remain with it if the deal goes through.

Though Lionsgate is headquartered in Vancouver, most of its operations are in Santa Monica, a few blocks from the Summit offices. Summit has about 150 employees, Lionsgate about 500.

As a public company, Lionsgate would be required to file with the Securities and Exchange Commission once it has signed a letter of intent.

The union of the two sizable mini-majors would bring the “Twilight” franchise under the same roof as “The Hunger Games,” which Lionsgate is banking on to revitalize its film slate. The last of the “Twilight” pics, “The Twilight Saga: Breaking Dawn — Part 2,” due to open Nov. 16, is likely to take in as much as $1 billion at the worldwide box office.

The first installment of what Lionsgate hopes will be a franchise based on the popular book series, “Hunger Games” opens March 23. The trailer for the pic got a boost with its target aud in running with Summit’s “Twilight Saga: Breaking Dawn — Part 1,” which did boffo business following its Nov. 20 domestic bow.

Since 2007, Summit co-chairs Friedman and Wachsberger have transformed Summit from a foreign sales company into a full-service production and distribution studio on the back of its successful gamble on film adaptations of Stephenie Meyer’s bestselling series of vampire-werewolf novels.

In April 2007, Summit arranged a $1 billion financing deal — a transaction that would not have been possible a few months later as the financial markets began melting down.

Last March, Summit closed a $750 million financing deal — a $550 million term loan and a $200 million revolving line of credit — that allowed the company to unshackle itself from some of its debt, increase feature production and fund day-to-day operations. It also paid a cash distribution to its largest investors, including Friedman, Wachsberger, Participant Media and private equity fund Rizvi Traverse Management.

Lionsgate and Summit have had discussions about a union going back as far as fall 2008, just before the bow of the first “Twilight” pic.

The merged entity would have more firepower in a market where the majors have scaled back on mid-budget films in favor of tentpoles and franchises — creating an opportunity for sizable indies to fill that gap.

Lionsgate’s stock has been up and down in recent years, but it appreciated by 28% in 2011. Shares gained in value starting in late August once billionaire financier Carl Icahn agreed to sell off his stake and end his long quest to take control of the company. Shares closed Friday at $8.41.

Unlike Summit, Lionsgate also has a sizable TV production-distribution operation that is home to series including AMC’s “Mad Men,” Showtime’s “Weeds” and “Nurse Jackie,” “Boss” on Starz and the upcoming Charlie Sheen sitcom “Anger Management” on FX. Its Debmar-Mercury syndication operation includes “Tyler Perry’s House of Payne” and “The Wendy Williams Show.”

Lionsgate has grown through acquisitions during the past dozen years under Feltheimer and Burns. The duo have orchestrated the acquisitions of film and video libraries including Trimark in 2000, Artisan in 2003, Redbus in 2005, Debmar-Mercury in 2006, Mandate in 2007 and TV Guide Network in 2009, as well as a stake in distrib Roadside Attractions in 2007.

Despite the battle with Icahn, Lionsgate remained an active bidder for MGM in 2009 and 2010 before the Lion went through its pre-packaged bankruptcy in late 2010 in a deal that left Spyglass toppers Roger Birnbaum and Gary Barber in charge.

There’s been speculation that Lionsgate has been looking to sell its half-interest in the TV Guide Network cabler. A Summit deal could accelerate a decision on what to do with the flagging asset, as Lionsgate may need to raise some cash to help it absorb the acquisition.

Lionsgate is nearly $600 million in debt and has about 13,000 titles in its film and TV library.