Frank, you can still have GM kits in a master
drum soundfont accessed by the appropriate
program change and bank select messages, for styles such as you mentioned(i.e., styles converted to Yamaha). For that matter, a
master drumfont could even have GS kits.
Sure, you can't use some currently available
wavetables, such as Bandstand for XG, but
since a drumfont uses mostly one shot
non-looped sounds, making one shouldn't be
There are many Yamaha styles that use 2 different drumkits on channels 9 and 10, but I am not sure if other non-Yamaha brand styles also do this. But whether they
do or not, at least adhering to the XG drums on ch.9 & 10 protocol, would be beneficial in providing consistency.