I don't know how fun it would be to hack but it doesn't seem to fit the idea of most people trying to duplicate real arcade controls for their MAME cabinets.
Here is a better link to the actual controller mentioned in the article:
http://www.microsoft.com/products/hardware/sidewinder/devices/SComm/default.asp
Well I don't know about that... it's a programmable, macro-atizeable, multiple input device... I think for an ambitious "hacker" it could be a cost efficient way of wiring up an arcade control panel (although I also think it would be neat un-hacked for some games).... *Shrug* YMMV but I see where the original poster was going with this...
rampy