I haven't tried. I've been a little reluctant to get any of those Xin-mos due to some of the troubles I've seen people post about them. For a two-player it looks like there might be some slightly annoying issues, but issues that can be overcome. Some of the stuff I've read on setting up 4 players have had lots of weird issues, and i haven't read any posts yet with help on solving those issues. I'm guessing it can be figured out... but for the potential trouble and effort, I'd go with a 4 player ipac instead. Easier to setup... but may not work for emulators that only like Joysticks.
Sorry I can't be of more help.