Yeah, I've tried playing the most basic shootie of them all - Space Invaders - on my Android phone and it was Failfest 2010. Duo-r was telling me that, on Android at least, you can use a Wiimote via bluetooth to play emulators. I just checked and you can do the same on the iPhone. So, that could work, but no buttons = no good. Not only are your fingers covering the action, but you keep checking to see if your fingers are in the right spot.
On another note, it just seems wrong that we should have to pay for TG games twice. But for people who are new to the system it's great exposure for the TG. For me, if it's not free, no thanks.