Chances are good with NVIDIAs GRID cards ( Stream Applications and Games On Demand | NVIDIA GRID™ | NVIDIA ). But this will be a *bit* more expensive than a GTX 680 - or even one of the 800 series. You need a GPU which is made for virtualizing stuff (in this example, graphics) - the GTX series (and even the TITAN) isnt suitable for what you are planing to do (may it would work with the TITAN, but I think you'll have about 5 to 10 FPS).
Also you have to remember: sending out 30 FPS (30 FPS looks crappy, but is the lowest rate I suggest.. everything below 30 FPS is just "eye cancer" in gaming), you will need a fibre-network (lets take a 1920x1080px screen, its about ~2-3MB (without compressing - Ill just take "raw data" for this example), 30 frames per second will result in 60-90MB/s - if you have 10 clients, you'll have a datarate up to 600-900MB per second - beside the game traffic (which is normally insignificant low). Or you put in some more NICs, 5 NICs, from which every single one handles 2 clients, this could make it possible with the traffic when compressing the frames down.
The biggest problem which youll encounter is the traffic - In general, I think its possible to render "older" games in a virtualization with a good hardware when its possible to render huge CAD files among the network these days.