I'm continuing to dig into the Gsharp code, especially the buffer classes and the midi back-end. I found a little bug in the midi library used by Gsharp and emailed the university group that maintains it about whom to submit the bug-fix to.
I also found a small redundancy in the Gsharp code and I expect I will find more things as I wade through the code, so I am going to request write access to the Gsharp CVS repository once the common-lisp.net mail server starts working again. It appears to have been down for the past few days and for this reason I haven't been able to join the Gsharp mailing lists either.