[Japper]

Last year I made one from a ~$5 joystick "Y" cable that I bought from Radio Shack and cut the end off it and used that by mounting it in a small box with switches.

I noticed a month ago that the Radio shack near me was closing these joystick "Y" cables out and I bought one off the clearance rack so I am not sure if they are still selling them or not but you might want to check out your neighborhood Radio Shack...

Also, I just searched the radio shack site and searched but this item did not appear, so you might want to go and ask them if the have any if you choose to go this route.

good luck