Basically, here is the thing:
Go through all of the Room of Doom pictures, and you'll notice that no two systems are the same, and about 90% of them are self-made ones. There are people using the same concepts, but nothing identical.
That's the whole problem with any sort of gaming rig. If you set it up, you can only make it perfect for one person. This rig looks nice for an Xbox and PC, but that would make it nearly useless for me, as I rarely play games on my PC, and would much rather do it out in the open. I also don't own racing attachments or whatever.
As I am working on my RoD now that I have a house, I have ideas that are definitely one of a kind. I know they wouldn't apply elsewhere.
No matter how cool or functional these chairs get, they are only cool / functional for a very small set of people. I doubt you would find anything that would sell well.