What you CAN'T do is make a current gen Xbox controller work on a 360.
However, I think you should be able to make an adapter that would allow the wired 360 controller to work on the current Gen Xbox...
With that said it's no easy task. I've made adapters to allow you to use PS1 and NES controllers on your PC, it's a fairly straight-forward process. It's rather easy with serial or parallel based devices mapping to a serial or parallel port. throwing USB in there is a completely different animal. It's possible but you better dust off your EE/Computer Systems degree before you start

I know a few people on these boards who could accomplish this. I probably could if I wanted to devote a few months of my time to R&D on the subject. Your best bet is to just wait it out for a commercial product to become available, it will take just as long and it's a lot easier to simply drop $20 on something like that then spend a few $100 in prototype crap and months researching.
EDIT: Thinking about it MS could probably just do this all in software with something like a dash update... Has anyone even tried just using one of these on their current gen Xbox? You never know, it might already work
