Elmofongo: There is a good chance it will happen, but looking at the 3DS not selling GBA games what the hell is taking them so long.
They never said they were going to sell GBA games on the 3DS. In fact they pretty much said they weren't. The ambassador GBA games lack any Virtual Console features and I suspect they're not 100% emulated. There's no restore points, no sleep (apart from the built in sleep function of some games, but this isn't activated by closing the lid), the game doesn't even pause when you open the home menu (and it's the cut down menu like the one you get when you're playing a DS game).
Basically, I'm fairly certain the games are running on some kind of hardware compatibility mode, perhaps the DS mode in the 3DS still contains the GBA mode of the DS. They're not going to be releasing GBA games on the 3DS Virtual Console until they can actually emulate them, and who knows if they'll ever manage that?
Elmofongo: Also even if they do sell GC games I hope they include some Third Party games from the Gamcube like Resident Evil Remake and 0, Metal Gear Solid: Twin Snakes, Eternal Darkness: Sanity's Requiem, Soul Calibut 2, Viewtiful Joe, Star Wars Rogue Squadron 2: Rogue Leader, and Tales of Symphonia and Final Fantasy: Crystal Chronicles.
Twin Snakes and Eternal Darkness are second party (but I guess since there's a licence involved with TS it's more like third party). Anyway, there have been third party NES/SNES/N64 games on the VC so I see no reason why there'd be only first party GC games.