You could definitely rig something up with a cheap IR receiver and something like a RPi or Windows PC.. and they make legit IR repeaters for exactly this use-case. RM3/4 etc is not really a good option for this, since you are adding unneeded complexity.
You will find that the Harmony hub setup is a rather good bang-for-buck when you consider all that it has to offer. I'm only playing with the RM3 mini because I wanted to see if I could control dumb devices like my tower fan in other rooms. I'm also going to test a friend's pool remote that works on RF. Otherwise I would only recommend Harmony all day long.
