One of the classic complaints against the 7800 is it uses the 2600's TIA for sound. Maybe that could be used as an advantage.

Imagine a TIA music editor which uses the 7800's graphical capabilities to display notes on a scale and to scroll in realtime during playback.

My only question is how to get compositions out of the 7800 and back to a PC so the creations could be added to 2600/7800 homebrews. Maybe via a SaveKey <-> serial interface?