I would love that.
it seems that they bundled it in with the Apple Audio Extension in later versions? that or some USB support extension. it would be rather interesting to get this thing working on a non-G3 USB Mac; although the only non-G3 mac I have actually has a G3 upgrade and is in fact not even a Mac at all, but a clone!
(and a 6500/275 but I stole the RAM from that to get 640MB, muhahahahaha.)
if it can be edited to allow any Mac to use it, that'd be something, and one less headache for all those that still have one of these USB iSubs and refuses to admit it.
IIRC they stopped being supported somewhere in 10.6 in OSX, so I think most people threw them out. They work very primitively on WIndows but can't be used in parallel with another sound output as only Bass as that's against the driver model.