the Greater Nomadic Council

Crazy--looking at the poll on the right side of the linked article, they don't even mention Lenny or Carl as possibilities. Carl's homosexuality has been hinted at more than once (most memorably in the recent episode with Homer and Marge as children, in which Carl says "man, I hope one day love comes sliding down my chute"), and Lenny's strange affection for Carl has been a running gag for years. My money is on one, or both, of them.

Good call. Although I would get a perverse pleasure out of seeing Flanders come out, it seems unlikely. Maybe either Lenny or Carl comes out and gets rebuffed by the other, forever damaging their friendship? If it's Smithers, I'm going to be disappointed. It'd be like them building up the hype for an episode that bravely declares Homer is fat.

Homer: "I'm gaining sixty-one pounds to go on disability!"

Yeah, I would like to see Lenny or Carl come out of the closet. Another good one would be Edna Krabapple's dawning realization that the reason she has stayed with that mama's-boy Skinner is her latent desire to be with women. I would have said Comic Book Store Guy, except for his passionate encounter with Agnes a few seasons ago. Herman, the owner of the military antique store, would be a funny one, but he may be too minor of a character. Maybe Patty or Selma? That seems kinda obvious though (despite their failed attempts at love), with all the man-hating jokes.

File these under "never gonna happen":
-Homer, Marge, Bart, Maggie, Grampa Simpson. That would be too much methinks. (Maybe Lisa though? That would certainly make the biggest splash.)
-Kurt Millhouse. Too snivling and icky.
-Chief Wiggam, Krusty, Dr. Hibbart, Seacaptain, and any character equally or less minor than Bumblebee Guy. The first three are kinda too masculine (although I could envision Rainier Wolfcastle or Kent Brockman coming out...); the rest would be too minor to make a big deal out of.
-Smithers. Too obvious.
-Barney Gumble. I just don't see it.
-Cletus. Too many kids.
-Apu. Also too masculine and too married.
-Mayor "Diamond" Joe Quimby. Too many womanizing jokes...but maybe...

So there's an initial thought. Smart money's on Lenny and/or Carl though. Bring on the controversey!

Lisa's too young to come out. Plus, she's shown a noted interest in boys so far.

I think you may be right about Lenny/Carl though. I really can't think of anyone other than Patty or Selma that would work and both of them are man-haters due to bitterness, not lesbianism. See their crushes on MacGuyver.

Lenny and/or Carl coming out of the closet is almost as blatant as Smithers. I don't think the recent showcasing of their homosexual tendencies is going to lead up to an outcome like this. Ned would be a good call! As Homer Jay said, "Damn sexy Flanders!"