Sorry about spamming all my thoughts here, but helps me actually do things when I first brag them here.
We had gaming night with RockstarRunner here and noticed that there was quite loud buzzing when the audio was silent otherwise. I tested all different kind of grounding things with no success.
Next day after I had less beer in my head I realized that I have 1GHz two channel digital oscilloscope and used little bit more scientific approach than just trying things. Well, it was bad cable. I'll get me coat.
But back to the business. Next step is to create wireless controller. Well, try to create one. I have few atmega328 microcontrollers, nrf24l01 radio modules I have used when creating wireless temperature sensors, lots of extra d15 connectors, male and female and if I grab pile of 4066 quad bilateral switches I think I have everything I need. nrf24l01 might not be best for this, but this would just be proof of concept. Maybe first just do some sort of mockup controller and then think about adapters for normal controllers.