Sounds nice.
Live instruments should be used whenever possible, of course.
Also, why not use Ogg Vorbis for this?
Also while at it, I think ScummVM should support soundtrack replacement for all games, where this is possible. That should be all kind of MODs and all MIDI games, except for the iMuse titles. Besides BASS, that would be at least those, I guess:
Maniac Mansion C64, EGA, Amiga
Zak McKracken C64, EGA, Amiga
Indy3 EGA, VGA, Amiga
Loom EGA, Amiga
Monkey Island EGA, VGA, Amiga (well, Amiga already supports this

)
Flight of the Amazon Queen
Gobliiins Floppy, Amiga
Simon the Sorcerer 1 & 2
Maybe we should file a feature request for alternate soundtrack support for all those games.