Needing multiple controllers to register the same inputs.

[Ashek]

So I'm working on a cabinet that will be relying on both the arcade buttons and various controllers to run everything.  My goal it so allow players to use pretty much whatever they want.  For example; if your using a PS3 controller you could easily play Dreamcast or N64 without having to switch what your using unless you really wanted to.  So I would need a half dozen controllers to all register to the computer as the same inputs.  Is there some way to pull this off?

Also, I was thinking of using 4 USB ports in the front for the different players.  Could I make a single controller show up as input 1-4 depending on which port its plugged into?

Thanks for any help on this one.  I'm still at the tossing around ideas stage but it'll be a relief having a clear plan of attack for when the time comes.