Thing is I want to use my remote in multiple rooms so Line of sight/bounce will not work from the pronto to the 543.

OK, I looked at the xantech stuff and it seems pretty expensive for the reciever modules. What exactly is the minimum I need to have in order to relay an IR signal from my bedroom to my livingroom 543 box?

You guys are sure that I can't have two 543's hooked up at the same time? One in the bedroom and one in the living room? I don't think both would ever be able to be activated at the same time so would it matter? Whichever one recieved the IR signal would send out the X10 code right?