You're getting ahead of yourself with Jamma boards. Capcom likes to control their IP. That's why so many of their games have a suicide battery. (
http://cps2shock.retrogames.com/suicide.html) In my opinion, Capcom, in order to cut down on the cost of manufacturing, made a motherboard (The A board) that will be able to accept other daughterboards (B boards). If you decide to go to other Capcom CPS2 games, you can just swap out the B boards. It shouldn't cost you $150, but only $50 for a new B board when you were a arcade operator.
In regards to what is the value of the B board, the simple answer is, it's whatever you can get for it. I have a Tokio game board. It was one of my favorite games. I was able to get it for $20. I would have paid $45. I have Super Puzzle Fighter 2 Terbo, got it for $75. I really should have only paid $50, but I wanted it for my wife. (We have it already on GBA and the "rare" PSX version)
Getting back to JAMMA, you'll need to replace the A board with a new game. I have a Killer Instinct game that will take the Jamma connection, but I have to do some special wiring for the kick buttons. The Jamma standard is 4 buttons per player and only two players (I'm sure someone will correct me if I'm wrong). Four player Capcom games will fully use the kick harness for the other inputs. If you have a basic game after 1985, the games should be interchangeable from the A board to another game.
By the way, don't bother calling DataEast. They folded up back in 2003.
Other links :
http://www.arcade-museum.com/game_detail.php?letter=M&game_id=8636 (get a copy of the manual and learn about the hidden characters)