Scott,
This would be a nice system if you wanted to open the door also. I don't like it because:

First: It would cost more.

Second: Who needs X-10 to open the garage? I wouldn't want a neighbor or repairman in my home without me being there so...?

Third: This would take one extra code on the IR543. With only 16 you might not want that.

Forth: You would be relying on the Pronto to send out not one but two IR codes. More room for error!

Fifth: I wouldn't want to use an X-10 remote to open the door when my car alarm remote will do so! This was fairly simple...wanna know how?

Just my opinion!
Chris Couture