Impossible for now? I wonder, is this something I can help with? Is the mapping not complete with GNR?
I like your idea of 7 wavs, but as with most Pinsound users, I bought it for the customization. Dizzy Ball should have piano since he is the keyboardist, Gilby Rolls should have something exciting like Out Ta Get Me, or Don't Damn Me (which you have already included).
I'd volunteer to help finish the project, if that is even an option...