Your game room is a dream Andrè!
In the end I would like to have a control panel set-up that will support all games[...]

Maybe weird, but I really don't like the multi-williams artwork around.
+1, the Mutli Williams artwork is a SHAME: very confusing with little to extra little images 
Andrè, turn that Joust back to his original glory AS SOON AS POSSIBLE! Running a multiboard is not what it is intended to

Thanks for your compliments !
Not sure if you know, but that "Multi-board" is _not+ your average xx-in-1 board from China running some ancient MAME version with lousy sound emulation you may be thinking off...
This is Jrok's Multi-Williams PCB. It does NOT emulate the games. It has the original processor running on the board !
The only thing different from the original hardware is that all the surrounding hardware is put into a FPGA chip.
It's like putting all those loose TTL chips that are on the normal Williams hardware into a single chip.
It plays 100% the same as the original hardware, as stated by many owners who can compare it to original hardware set-ups.
I have absolutely ZERO problems running this board in this cab. Reasons ?
1) It's 100 times more reliable than the original hardware
2) I can play both Robotron AND Joust on it...the two Williams games I love the best
3) it is NOT emulation....we all know how I feel about that

IMHO FPGA's are the way to preserve those games. In the end we will not be able to get separate DIL TTL IC's anymore. I am always 100% for original hardware, but this board is an excellent alternative for it.
(For some who don't know (Etienne f.i. already asked about it): This board does not run Moon Patrol for a reason. MP is not an original Williams game but a license. Hence, it works on a totally different hardware platform. All the other games run on (about) the same hardware, so that's how close JROK stayed to the original hardware...)
So, no the Jrok board will stay where it is. I read that it's worth at least 300 USD now by the way

Here's the whole story by Jrok. You should also read the rest of his pages.He started out by doing reproductions of PARTS of the original hardware, making PCB's to replace original one's. So, step by step he learned the Williams hardware in and out, and only then he created the FPGA.
http://www.jrok.com/hardware/wsf/