I am working on a D-box style motion platform. The project is in progress currently but I made a video about first test with Dirt2.
Home made D-box style motion platform, with commercial linear actuators. Contoller system : Arduino uno and Motomonster shield. Feedback about actual motor position: 10K rotary potmeter . Control software: Xsim Power : 12V 30A PSU commercial. Actuators: 24V 150 mm speed:60mm/sec 2 axis with 3 effect: Longitudinal force, up and down force and gear shift effect.
If you have any question or idea about this solution, please let me know.