Don't you use the VESA mount points to mount the device to the TV?
Yeah, maybe I should clarify...
I'd be mounting the device directly to the wall somehow... custom built shelf maybe, but probably just some metal brackets. It doesn't have to be pretty 'cause it would be hidden, so that's not a difficult problem to solve for me.
Getting the required power in the right package is the issue. I figure we're close... ultraportable laptops and tablets are so thin and light, yet are obviously capable of handling HD content. Really seems like it'd be easy to tuck one back behind the screen, and I might just try it. Wanted to see if anyone else had done it, though.
The whole point in this case is that this is in a room without surround sound, so there's no receiver or any other equipment except the HTPC, so I could ditch the little table currently under the TV and make the room look a little cleaner.
I'll eventually post pictures if I end up with a successful configuration...