An FYI only: Macromat (makers of Techtool Pro 5) are currently looking into an issue wherein my 30GB (pre-allocated) virtual disk (Fusion 2.0.2) was destroyed following a routine volume optimization. They are currently advising that users on the new Techtool Pro 5 version NOT include the virtual disk when performing disk optimization.
Hopefully this saves somebody some heartache. I'll post an update once I get some follow-up on this matter.