@jacreason Did you ever figure out how to do this. I just bought the same board and want to be able to two player xinput (gamepad) and also one player with two stick play if I can with it.

@mitu - I was able to use mame4all which sees that roller correctly - very confusing how the retroarch cfg works..
Example:
To see the spinner for arkanoid I had to switch to mame4all and looking at the input shows J1 RetroPad -X and +X for the controls... I don't know how to map that here as the spinner doesn't provide anything like that in the mame config (tab) and when I edit the .cfg file I tried adding the following:
input_player1_left_axis = "-0"
input_player1_right_axis ="+0"

with no luck... still unable to get the spinner working - howbeit the trackball works out of the box with mame4all.... lol

Somebody needs to write up a config walkthrough for retroarch and that joystick system... greatly.