I don't see the problem with the touch screen and buttons issue.
There aren't very many DS games that make you use the touch screen, buttons, and d-pad all at the same time.
It's almost always the touch screen by it's self, the touch screen and buttons, or the d-pad and buttons with the occasional use of the touch screen.
All you'd need is the classic controller and a Wiimote for pointing.
Either way, I can't see a DS emulator on the Wii anytime soon, but it could be possible.