Yeah, new stuff is happening, I'll give a summary here.
I put up a
webpage so I don't keep bumping the topic every 5 minutes with minor changes.
I'm pretty sure I have the rerecording part all worked out. The only reason games desync should be that savestates aren't properly implemented. (Savestates are a relatively new thing, there was a long debate about whether to include them in MAME, so most games don't have proper support yet)
As far as I can tell, I have NeoGeo savestates fixed. Gradius desyncs occasionally on me, and I fixed savestates for Karnov, the grandest arcade game of all time!
Now for the patch thing, I'll put the patched source on my website in a few minutes, but I'd like to figure out if I'm generating patches wrong or something. Are you getting the source through CVS, shakespeare?