Here is a contender for you. This is my 6 box setup. I used it to 6 box eq1/eq2 and 5 box WoW.
I am not active right now (catching up on good single player games) but will come back eventually.

It is rather late at night (and I just found this site) so I am going to be brief.
I used three ergotron DS100s to mount the LCDs (2x24in + 4x20in).
I used 5 regular IBM keyboards and 1 leftie keyboard (plus the 6x Logitech marble mouse trackballs).
This takes alot of space but I hate KVMs. Everything is on UPS. Physically I am very happy with this setup.

Sorry for the huge image sizes but they are straight from the camera.

DS100

Up close view:



The whole setup: