You are barking up the wrong tree. RAM drives are not accessible, besides with ESX you don't want those anyway. You wouldn't put critical systems on a RAM drive, that's a disaster eventuality.
And with PCI-e you can't centralize anything via a direct connect, you should be look at TCP/IP networking options not hardware specifically connected to a machine, you can't centralize that. No way for another ESX to share the same connected hardware but a network solution works. NFS maybe?
