Neo Cab is a great game! No real rhtym games as inspiration. I initially sat out playing with procedural music (Eno, Cage, Terry Riley, the works) which is how I came to the Midi for Godot project by arlez80, but threw all of that out to focus on something more manageable. I also played Jazz in Black & White a while back which is a very simple and elegant example of using music as a core game mechanic which might have influenced the decision of a rhytm game as well.