I don't really think the 3DS would make sense as a platform for a Stadium game though; I think handhelds are better suited for mainstream Pokemon games. Since Stadium games are really just watered down (obviously with their own perks, though) Pokemon games made for non-portable consoles. If Stadium were to be on a handheld, I'd rather play a mainstream game with a more solid plot and developed overworld. But I wouldn't want to play a mainstream Pokemon game on a non-portable console, either.
I guess, in my opinion, it's all a matter of casual playing vs. non-casual playing.