Klaz just pointed out something in the Wrangler thread.

All music in games is performed in the Vblank - regardless of CPU speed (8/16/20/68000/10,000,000Mhz) this would always be 50Hz or 60Hz.

I'm going to have to say I agree with Klaz and something I also mentioned earlier - Your MSTE has VSYNC issues :)

As for "how far does the ULS bug go" - unfortunatly - all the way back to release 1 in November.  HOWEVER, nobody else is getting the extreme speed issues you have described (this is not to say we don't believe you!) - So lets look over those JPGs of the inside of your beastie. How are you connecting to a screen? Monitor?