GOOD MORNING: Suzanne Pleshette and Tom Poston have been dating but she told him before they get more serious she wanted “a big rock.” So, Tuesday at the Bel Air Country Club, Poston produced a paper bag in which there was a huge chunk of rock — 57 carats — set in platinum! “I almost had a heart attack,” says Suzanne. No, they are not engaged, but she admits, “Someone finally topped me.” The duo had dated twice before — before marrying others … Martha Coolidge, whose HBO “Introducing Dorothy Dandridge” is up for 11 Emmys, admits to me, “The feature scripts I’ve gotten don’t hold a candle to the TV stories I’ve done.” One of the TV’ers is her current “Flamingo Rising” for Hallmark Hall of Fame’s 50th anni, to air on CBS. She’s shooting it in St. Augustine, Fla., with stars William Hurt, Brian Benben and Elizabeth McGovern — and the world’s biggest drive-in movie screen. Production designer Jim Spencer (who was nominated for “Dandridge”) is building the screen, which Coolidge tells me is 80 feet long — and built to (hopefully) withstand the approaching hurricane(s). She describes this movie (from Larry Baker’s novel) thus: “I hope it does for this generation what ‘Dr. Strangelove’ did for me.” The visual f/x will make the telefilm seem much bigger than its under-$10 million budget. The drive-in is next door to Marineland and Coolidge said, on her day off, she and 11-year-old son Preston swam with the dolphins; “This is not a hardship location,” she admits … While Coolidge commented on the paucity of good bigscreen scripts, she has found one to do: “Blowing Up” by Nick Kazan, “a comedy about the first nuclear reactor accident,” which Coolidge will do with Kathy Kennedy and Frank Marshall.DOUG CRAMER IS BITTEN by the B’way bug. Cramer, who sold his Calif. ranch and Bel-Air home and moved to N.Y. (and Conn.), has five shows in various stages of development. He’s nixed network calls to do shows, instead concentrating on theater. The first is “The Tale of the Allergist’s Wife” for which Charles Busch is writing new scenes following its success at the Manhattan Theatre Club. It bows at the Barrymore Nov. 2, starring Linda Lavin, Michele Lee and Tony Roberts. Cramer’s producing with the MTC’s Barry Grove and Lynne Meadow plus Daryl Roth, Carole Shorenstein Hays and Stuart Thompson. He hopes to follow with “The Sex King” by Bill C. Davis (“Mass Appeal”), a comedy-drama about a man who runs a callgirl service. Cramer’s again teamed with Meadow; Judd Hirsch does a reading in Sept. … Cramer reteams with Roth for “Take Flight’ a new musical by David Shire and Richard Maltby … I was talking with Tony winner (“Cabaret”) Joel Grey Wednesday as he was strolling down 5th Ave. at 55th — as he readies to head overseas with a stop in London for meetings about “Harry Potter.” He can easily adopt an English accent, as he had on “A Christmas Carol” last year, playing the Ghost of Christmas Past (“Pahst,” he corrected). He’ll detour via Toronto to voice the animated feature, “Ferret Tina,” which he describes as “a ferret’s answer to ‘The Lion King.’ ” He’ll be seen on the bigscreen Sept. 22 with the release of both Michael Ritchie’s “The Fantasticks” and “Dancer in the Dark” … After many years of TV movies and miniseries, Jerry London’s off to N.Y. to direct with exec producer Sidney Lumet, “100 Centre Street,” starring Alan Arkin. London says he’ll alternate directing with Lumet on the hour-long drama about N.Y. night court. They’ll shoot three-camera, high definition. WITH APOLOGIES TO MARK TWAIN, who said a report of his death was exaggerated, Karen Kramer tells me a report on the Internet that her husband Stanley Kramer died June 6 are untrue. “He is alive and well and we will celebrate our 34th wedding anniversary Sept. 1 and he, his 87th birthday, Sept. 29″ … On the Warner Home Video DVD of Alfred Hitchcock’s 1959 classic “North By Northwest,” Eva Marie Saint hosts an hour-long docu also including Ernie Lehman, Robert Doyle, Martin Landau and Pat Hitchcock. Hitchcock’s daughter Pat admits “My dad loved blondes, that’s for sure. And he could see something in people that others couldn’t see. He could see classiness and he could see Eva Marie Saint as the classy person she is, instead of the kind of working-class parts she’d played up till then.” Eva told me Hitch told her at the pic’s finale, “Promise me you’ll never do a sink-to-sink movie.” She admits, “I didn’t promise him.” She admitted to me, “I’ll never know how or why he saw me as a sexy spy lady for the film!” She also recalled to me, “Cary Grant said to me on the first day, ‘This is just a spoof: You don’t have to cry’!” P.S. Much of the classic cropduster scene was shot — on stage at MGM. The DVD’s in stores Aug. 29 and the docu airs Sept. 10 on TCM followed by the movie … That’s shoe biz: Stuart Weitzman opens a store on Rodeo Dr. in Dec. Among the dozens of stars who’ll wear Weitzmans on their tootsies at the Emmys will be three who are expecting: Kelly Williams (“The Practice”), Ming Na (“ER”), and Jane Leeves (Frasier”). Weitzman promises to make their shoes extra comfy … Among the extra special items in the silent auction at Barbara Davis’s Carousel of Hope gala Oct. 28 at the BevHilton: a Valentino ensemble valued at $25,000, which can be worn during five nights at the Hotel Ritz in Paris, seats there at the couture show next summer, having flown there via American Airlines. Total value for this package: $55,000. Mon Dieu, Barbara!