Tried an USB soundcard yet?
-OP, sorry for being off topic-
Yes, I did. I bought the latest 5.1 channel USB Soundblaster and after fiddling with AHI, got it to work and sound great! Problem was, at the time, I had been using a flash drive on my A2500 (no HD) and there was serious conflict. No matter how you adjusted the buffers, etc., processor just couldn't keep up. Now that I have gone back to using a real SCSI HD, I may try it again.
I was thinking a real AHI soundcard such as the Sunrize 516 would be better, more flexible, out of sight, could digitise in 16-bits and keep the Soundblaster down in the basement where it does a much better job than the built-in sound of an iBook :-)