Dreamcast Controller > PC Adapter

I have seen a whole slew of adapters for plugging PSX and Saturn controllers into the joystick or USB port on a PC. Is there an adapter that will allow you to use your Sega Dreamcast controller as a PC Joystick? How hard would something like that be to create?
I don't think it would be particularly difficult, with the Maple Bus info that Marcus Comstedt has posted on his site.
Kamalot: Where'd you see the saturn => usb connectors? I've been looking all over for something like that for my emulation.