What you want should be quite an easy setup, it's a live system runing from usb with some kind of kiosk application.
Sounds pretty straightforward but why would you want to run it from a usb stick?
Your choices will only be restricted distro-wise, and you could use various different live distro's running from cd or dvd already tailored towards multimedia like
Sabayon Linux or any other live distro with an already setup kiosk environment.
If you really want to go usb, I would select a kde-based distro to run from a usb stick and install kdekiosk on it.
There's tons of info on this subject on the net, just yell if you need help finding what you're looking for
