What about having our production number and year put on. Like 46 in 99 Okay, that bites, but my husband and I were thinking about getting plates that had our fire department call signs on them: MHF1125 would be mine.
But I'm thinking the ones you are all making up sound a lot more fun.
What about UFO like someone suggested a long time ago. I thought that was really nifty. And of course, someone already has VXTREME which is really clever.
My two cents:
VX.INFO for Scott 
MIB for anyone with a black one.
REDOCT As in (The Hunt For...)
CODERED again, for red ones
NUCLEAR
PROJECT
ADVNTUR
NTRPRIZ (Enterprise)
I could go on, but I'm just playing with my wordweb.
Return evil for evil to no one...as far as it depends upon YOU, be peaceable with all men. Romans 12:17, 18