Modern multiseat options

I want a multiseat box, 1 seat as a desktop, another as a htpc/steambox. I'd like to know if any new projects have come out to make this easier, more functional, and more economical. I really wasn't able to find a good up to date comparison of options.
Approaches I've heard of include Parallels, LXC (Linux containers), multiseat X, Wayland, but I have no idea which is best, or something else.
I'd like to use a single GPU to minimize hardware costs, although a solution that leverages an integrated GPU would be OK, so long as both are hardware accelerated.
Wayland is new, will it allow anything like that?
Can a core boot compatible motherboard help get around problems like limited # of PCI express lanes?
Any requirements about GPU hardware (AMD VS NVIDIA), Drivers (open source VS proprietary), or anything else?