There is a INTV II on ebay right now, as is but comes with a working (according to the seller) power adapter. I need the controller for one I recently found with no numbers on the keypads.
It's about $25 shipped, maybe we can work out a deal?
I got mine at an estate sale for a quarter, if you can believe it. It works and came with everything and like 17 games, but I really want good controllers for it.