If you think you might want to ever run a Williams arcade game in your house, you need to buy the WMS board.
The problem is that jrok does not have a website you can visit to order. You need to contact him via email or through the Killer List of Video Games forum, with a private message. I know, I know. But this board is worth it.
Here is the website for the board: http://www.jrok.com/hardware/wsf/
The game list:
The price is $190 (I think.)Defender, Stargate, Joust, Robotron, Bubbles, Splat, Sinistar and Blaster. Although Blaster is more of a generation 1 "plus-a-bit" in terms of what the hardware can do. Out of that list Sinistar is the oddball as it has a vertical screen, so it's included only to complete the set and for use in a vertical cabinet as a replacement for an original boardset. Although there's nothing to stop it being used in a JAMMA cab.
Here is the thread on the KLOV site where people talk about getting their boards:
http://forums.arcade-museum.com/showthr ... 72&page=16
It costs two or three bucks to register on KLOV, so that you can contact jrok. (I know, I know.) You might be able to find jrok's email address on his site, at www.jrok.com.
If you are going through the KLOV site to send jrok a private message, here's the link to do that once you have registered: http://forums.arcade-museum.com/member.php?u=35049
I am buying a backup, because if anything ever happened to my WMS board I'd be livid. Happy gaming to anyone else who gets one!