I build one myself. As board i use this one. It basicliy is plug and play. PC recognises as an seperate controller. Comments on Amazon say, multiple boards will work simultaneously but i havent tested it yet. You need an adittional sottware if you use switches like an ignition key or parking brake, which stay in "on" position, because you need an input when pressing and releasing that button/swich. For that i use AutoHotKey and i wrote my "own" script.
Also i use the board from an old Steeringwheel but that is a lot of work and soldering