If that CBS Dallas reunion special (Nov. 7) made you wistful for the glory days of neckline-plunging, face-slapping entertainment, rejoice! ''J.R., Sue Ellen, Miss Ellie they're all coming to a big screen near you!'' says screenwriter Robert Harling (Steel Magnolias). Harling, an '80s TV enthusiast ''Knots Landing was Balanchine, as far as I'm concerned'' recently met with director Robert Luketic (Legally Blonde) about casting a Dallas movie (tentatively for 2006). He wouldn't comment on rumors that Brad Pitt is an early choice for J.R. But he did give up that his Southfork residents live in a post-Enron world, with J.R. at the helm of Ewing Energy and Lucy Ewing vamping like a Hilton. ''It's Dallas on acid,'' he promises. ''Every woman in the cast is Lady Macbeth and every man is Macbeth.'' Meanwhile, back at the ranch, the original Bobby ''It Was All a Dream'' Ewing has his doubts: ''It's one thing to have a new James Bond,'' says Patrick Duffy. ''But to have to duplicate hundreds of millions of people's [idea] of 'Who is Sue Ellen? Who is Pam? Who is J.R.?' That's a lot to ask an audience to do.'' Because Dallas fans find it so hard to follow twists.