Want to Buy WTB: Horseman 4x5 monorail tripod adapter

I'm looking for the piece that connects a Horseman monorail to a tripod - it has a knob and gear and fits on one side of a Horseman rail. I just need the adapter but I'd be willing to buy it with the rail if that's what you have for sale. Heck I'd even buy a whole camera carcass to get this piece if you're selling it cheaply enough!

Thanks,
Duncan