I build 3D Multiseat
Multiseat - a system with one case and several graphics cards, monitors, keyboards and mouses. Allows multiple users to work simultaneously with one computer.

In the configuration described 2 user can play 3D games DirectX9 using wine-1.0, for example, Heroes of Might and Magic 5 (HMM5), WarHammer 40k (WH40k), Serious Sam 2 and others are not impeding each other. The system easily expands to 4 seats.