You'd be surprised how well IR signals bounce off walls, especially with universal remotes which tend to have more powerful transmitters. I'd suggest just trying without doing anything, and seeing if it doesn't just work. If that doesn't work, you could strategically place simple reflector for an easy solution.
A more robust solution would be one of any number of remote IR transmitter systems. These are often used to control components in another room, but it would work for your purpose as well. Basically they consist of an IR receiver, some wire, and an IR transmitter on the other end. Putting the receiver in the front (out of the way of the screen, obviously), and then run the transmitter either right to your projector, or just face it backwards from someplace convenient in the front.
This should work with any remote, universal or otherwise. BTW, if you haven't already found it, I highly recommend
www.remotecentral.com for lots of good info on universal remotes, including relative transmitter strength.
Hope this helps,
-- Dave
