But your email gave me an idea. Rather than use Hydrogen (which I really like) or another percussion program to produce drums for any particular piece of music I'm working on, I could simply use one of the percussion kits in one of my MIDI tone generators, which maps a whole array of percussion from bass drums to snares to toms to hi-hats to everything else, to the various keys of a MIDI keyboard. Then I can simply use the keyboard skills I already have to "play" the drums in real time and accompany my already recorded tracks of piano, organ, etc.