So basically bracket mounted fixed pulley? Could be hard to come by. Simple plastic pulleys are no prob, actually you could check here:
http://www.sportsmith.net/Categories...8-62fb4c111966
Maybe you can find a metal "C" bracket of the right size to mount it on. You know the type I mean..with a hole on each arm and at the top.
BTW, at that place you can get cable, etc...which may be worth it as that rope is gonna stretch.