This is kind of a toughy, and I can only guess at some possibilities.
1. You will need a learning remote with sufficient capacity to learn all the Bose commands, because I am not sure if there are any remotes out there with codes for Bose LS28. Something like one of the Sony’s depending on how much you want to spend (RM-VL900, RM-VL1000, RM-AV3000).
2. You can learn from the LS28, but of course it will be IR.
3. The second room thing is a little harder. As another guess, you might be able to use an RF capable remote, like the RS 15-2117, or the URC 9910, to send RF signals from the second room to the Bose in the first room to be converted back to IR. Either of these should have enough learning for the limited number of commands you would need in the second room. You would probably have to learn these commands from your second room remote.
4. I am not familiar enough with the RF devices to be sure they will work. If edmund sees this, maybe he can clarify.