Thanks for everyone's input. Some of you clearly understand where I am coming from, others apparently do not. Yes, all tube amps put out heat. But dependent on design, tubes, and class there is a very wide variation. For example, I was out of town recently for three weeks and loaned him my office systems PrimaLuna tube amp. He had no heat issues whatever, but felt the amp, while very nice, was not in the league of the 518 (which I agree with him on).
The Line Magnetic is Class A, and uses some tubes that run extremely hot. Thats a very different situation than normal in the tube world. I once had the experience of using an 845 based amp, with heat output not even quite to the level of the 518ia. I used that in my office, which is 10x11, and even with the door open, and the ac running it was too hot to work in the room. I did use it for a couple months the next winter, and after an hour of use, it had raised the temperature of the entire upstairs of the house by 5 degrees.
I'm going to have to agree that the advice from wlutke, testpilot and others. This solution won't work. Now my problem is that, given that he loves the sound of that Line Magnetic amp, how do I possibly find something comparable to it in the same price range :(