I did this.
I had an asteroids harness and converted it
It took me about 5 days to convert it
My back will never be the same LOL
You will need some schematic skills to do it.
I am an electrician, so had a bit of an advantage. And I did bulletproof the harness - all new pins, and heatshrink on the new edge connector
Pull the trigger Zinf, and I will help you convert it mate
I made a diagram (Admitedly its for an LAI version, but the bulk of it is the same)
Diagram
http://www.dsbelec.iinet.net.au/LUNAR_LANDER-LAI_Schematic_Dezbaz_FINAL.jpg
Give it a go, maybe between us we can come up with an atari diagram similar to this one