MDS - I believe that Lutron came out with some RF switches which are actually directly compatible with the RF line of URC remotes so that you don't need line of site to control the switches but can just install the switch and control it via RF from the URC remote. No IR funkiness to deal with.
There are some solutions out there, but nothing which is super reliable if you are talking about doing it with a IR 'across the room' blaster or a mirror.
You may want to try to switch things out for a Insteon dimmer system with this:
http://www.smarthome.com/2411R/IRLinc-Receiver-IR-to-INSTEON-Converter/p.aspx
This will keep the IR for the lights at the front of the room, while the adapter listed will convert the IR signals from your handheld remote (any brand) to powerline communications which should work fine with your wall switch.
It isn't cheap, but it is should be extremely reliable once it is setup.