Avenue Pad 6 huh... I don't get the big deal, not exactly my favorite design. Should try to get the most cash I can out of it...
Genesis 6 button controller is missing 1 button. On PCE side you have 6 buttons (I to VI) plus direction and 2 more buttons for Select and Run. Genesis do not have anything to map to Run button. I checked, I couldn't find much about SNES 6 buttons pad but SNES Advantage and similar arcade style joysticks could probably be hacked. It won't be easy though as you'd need Three 74HC157, a 74HC163 for rapid fire option, and you can find schematic at http://nfggames.com/forum2/index.php?topic=3734.0 You'd need to figure how to modify SNES controller. Oh yeah a different cable with Turbo Duo/PCE mini 8 pin or Turbo Grafx 8 pin end. A dead TG16 or PCE controller would have the cable and parts (one 74HC157 on 2/3 button controller though, get second one elsewhere) EDIT: i can't count :/