It B nice to have Xbox support on mac os X I have it working but not many games have support for it. Just a suggestion.

Have you tried it? I know that the Playstation 2 gamepad is supported by Vendetta.

Vendetta doesn't support more than three mouse buttons, so if your game pad is sending mouse button presses instead of joystick ones, then it won't work. If I remember correctly, you can use USB Overdrive to set the mouse buttons to act like joystick buttons in Vendetta.
http://www.usboverdrive.com/

VO does support more than 3 mouse buttons. I use 5, myself. From my wgaf.cfg:
bind MMBUTTON zoom0
bind LMBUTTON +Shoot2
bind RMBUTTON +Shoot1
bind XMBUTTON2 +Shoot3
bind XMBUTTON1 Activate

I need to get around to changing XMBUTTON2 to something useful, I never use 3 weapon groups...