My '73 Commando carried '850 COM', my '76 Guzzi has always had "RVDRCI" ...I wanted ARVDRCI, but we can only get six characters in Oregon. I've been trying to come up w/ something clever for the '08 when I get it, but it just hasn't struck me yet. Heard the Beatles "Ticket to Ride" on the radio t'other day and thought 'TKT2RD' ...but in the song she gets the ticket to ride and he gets left in the lurch, so nix that.
One of the best one I ever saw was 'ML8ML8', ...from that you should be able to name the make/model/color of the car it was on.