I really hope someone would make this game. It's such a good match and fits all the tenets of a casual game for Windows Mobile. Easy to start, quick to play and addictive.
How would one play this game? we'll, just use any 5 keys in the keyboard to represent the Green, Red, Yellow, Blue and Orange buttons. In this case the Q,W,E,R,T keys. You probably don't need to simulate the strum bar but you can use the camera to detect the change in orientation to initiate "star power" (typically activated by tilting the actual Guitar in the original game. The guitar has a built in accelerometer).
Multiplayer? Through WiFi / Bluetooth of course. You can also try GPRS or 3G but the latency would be terrible.
Wouldn't it be nice if a few friends got together, and each picked an instrument (like the Rock Band game), go to a quiet place like Starbucks and jam on their phones. That'll be utopia for a Guitar Hero fan.
What do you think? good idea?