That would be awesome. Even just something to hijack the FM synthesis or the samples. As far as programming, tearing up the roms would be a start. Oh and then I read the audio reference for Snes on wiki:
Processors    Sony SPC700, Sony DSP
Clock rates    Input: 24.576 MHz
SPC700: 1.024 MHz
Format    16-bit ADPCM, 8 channels
Output    32 kHz 16-bit stereo
Effects   
ADSR envelope control
Frequency scaling and modulation using Gaussian interpolation
Echo: 8-tap FIR filter, with up to .24s delay
Noise generation
That's alot.

If it can combine the 4 GB channels with the snes channels, that would be awesome.

Also, it seems like you can run SNES code from the SGB on the snes, could make for a cheap snes flashdisk
But it does look like it needs some serious programming skills.

LSDJ SGB edition please

Fascinating, thanks for posting this!

Never seen this before. It looks a bit like how some GB games took advantage of the GBC and had full color. Also neither the SNES nor the super game boy are particularly hard to come by. Could open up all kinda interesting things. Extra sample channels?

that article's great. thanks for posting.

I've been working on the supergame boy lately. I like using the snes for a bunch of reasons, big screen, controllers, etc. I read on the wiki and found some of the games made use of the snes sound engine. Then I found this article :
http://blog.scoutshonour.com/post/2424872085 by Christine Love
Saying basically that you can hijack the snes sounds and visuals though the sgb. Looked around for awhile and can not find anybody who has taken advantage of this insanity. For instance adding 2nd controller options with lsdj with something like Trippy H controls (reverse, scratch). Anyone else notice this?