Disney already has a handheld console (I forget the name of it). My brother's kid got one for Christmas. I tried out it briefly. It wasn't too bad. It kinda looks like a colorful PSP and it uses cartridges. The game I tried was simplistic, but fun. Kind of like a browser game.
Overall, I'd say that Disney could pull this off well. Make a cheap, kid-friendly 3D game console, and they'll give Nintendo a run for their money.