I think there exist suitable x86-on-PCIe -cards. "Only" the SW needs to be made. The SW work needed might be too much vs getting cheap x86 node and connect to it via RDesktop...
+ If a-eon x86-on-PCIe custom HW would be made, getting M$ OS support for it costs millions I believe ... let's not enter there!
I agree Rdesktop and VNC solve that easily, besides there exists towers, that makes it easy to fit two full size motherboards into one tower.
