Demultiplexer circuit for console controllers

[RGB32E]

Has anyone out there built demultiplexers for any console controllers?  I ask this as I want to build a 6+ button gamepad interface (SNES or Genesis 6 button) for my arcade setup.  Arcade games use one wire per button, unlike most all console controllers.  I've gutted an original Genesis 3 button and NES controller and ran discrete wires for each button + ground.  This can become a pain when trying to run more wires... (i.e. 13 wires).

If any of you out there have dealt with this before, and have solid solutions, let me know.  Thanks.

[Adeptus]

If you do a search on this forum, you'll find info on hooking up Genesis (aka MegaDrive) controllers. Megadrive 3-button controllers use off-the-shelf chips, for any more than that you usually need to program your own microcontroller.

I saw code & instructions for a micro-based PSX decoder (on these forums, about a year ago from memory), but due to the number of pins on the chip they were using, it only had about 4-5 usable buttons. I guess you could move the program to a chip with more I/O pins (making whatever chip-specific changes necessary) and get the rest of the buttons working...

In other words, 3 buttons = easy, more = not-so-easy.

Not solid solutions, sorry, just pointers in the right direction.