I say its theoretically possible, but would require extremely major modification of both ESXi and the fglrx drivers, so not something you could just make some instructions for. I am curious as to why you would want to do this. I am also missing the connection to reusing the server for headless Windows server.
I would think it would take a professional coder much more than 20 BTC worth of time to complete a project of this magnitude, even at the all time high BTC/USD exchange rate.
I do, however, like your thinking because sometimes it is unconventional ideas like this that spur innovationa and development.
BTW, are you the guy with the youtube videos about silver?
Why would you have to mod the fglrx drivers ?
Im not an expert, but the fglrx drivers are for Linux and I would be really surprised if someone could get ESXi to install them. As someone mentioned earlier in this thread, ESXi is not Linux, might appear to be but it is a proprietary OS. Someone with more knowledge please correct me if I am wrong.