Operation Insane – Pre-Planning

I have had the most insane idea I’ve ever had cross my brain this afternoon. But before I can pull this off, I need some help.
I know I have a good cross section of Bemani sim users reading my blog; I also have a good chunk of Mac users. As such, I need recommendations for a PSX->USB adaptor that can take two controllers at once and doesn’t have any huge outstanding issues with Mac compatiblity.
Something that comes with configuration software would be even better.