the sites ranwithrsd posted should get you the info. you need for tags. Basically you will need to join the MD state Beekeepers Assoc. The treasurer of the assoc. (I believe that is Christine Goldman for this year) will provide you with the form you will need to get the tags from MVA. (The assoc. will ask for an extra fee for this, I think $15 beyond the annual dues of $10.)
I got mine last August. I didn't request a special number and got BEE 0063. Really cool looking tags IMO.
I have been watching this thread and had a thought. In TN we do not have front plates. I think I will have a plate made for the front of my van with a phone number. I thought something like Bee Catcher as I am on the list for swarms. Another thought was house/mailbox stickers. Just use these on chrome bumpers as they would be hard to get off cleanly from painted and plastic bumpers. My old full size conversion van is not much to look at so I may put these on the door as well. The first idea may make sence to those in states with just rear plates. Once made it is your till you loose it or damage it(had one on a 3/4 ton pick used in the nursery get torn up going into this one feild because of a wash out).