just splurged a bit on one of these:
http://www.ebairsoft.com/full-auto-tracer-silencer-tb631-p-6773.html - I've already got a TM tracer unit for my MP7, but it not being QD and not looking 'right' finally got to me, I was going to buy a dummy silencer and try to mod the TM internals to fit, but I'll try this one first!
Also picked up an emerson MS2000 distress strobe dummy, hoping to use it as the basis for an 'innovative' (read batshit crazy, and probably doomed to failure) anti-fog solution for goggles/glasses.