I don't know about you, but I think this wall unit from Italian firm MisuraEmme is quite attractive, it's only failing that it's the sort of furniture that tends to dominate a room to the exclusion of any ratty furniture or knick-knacks you may own. But the integrated television unit is an especially nice way to hide a flat-panel when it's not in use.
I didn't bother looking at the price as I'm sure it's painfully out of reach for most—or at least me—but I really like it in theory. The only real issue I could see with trying to make something similar on your own is that most flat panel TVs have a lip on the bezel that would prevent the display from getting right up on the glass, which would be critical for making sure you get the most light through the front.
What do you guys think about wall units in general? I've actually always been a fan, even down to the wood paneled versions of old. Then again I stay in a sort of raggedy hotel in the Florida Keys just because some of the rooms have room controls in a sloped wooden panel between the beds, so I may have a bit of a problem.