I've been going through the motions of getting something similar myself; I'd like to build my own HOTAS for Star Citizen. I'm a mechanical engineer by day, though, so my electronics knowledge was a little lacking when I started out. I've since learned all this.
The quickest way to get the electronic side of things done would be with an Arduino. Get yourself an Arduino Uno (available locally for about R300-400), get a second chip to use in the project as the HID controller (about R50, last I looked), and then look at
the Unojoy project.
If you don't want to go that route, some folks over at avcom.co.za has had success with importing boards from
LeoBodnar. They're a company that builds racing car simulators for the likes of F1 teams, and they sell the HID boards they use as well.
If I do ever get my prototype working well enough with my arduino, I'd probably jump over to a LeoBodnar chip, since it actually has a driver interface. However, time and finance pressures has caused my project to stagnate a bit for now. Feel free to PM me if you want to dig into the research I've done!