"Low-power" HTPC - advice?

[Norris2k]

I'm very happy with my Q1900DC-ITX.
- powerful enough for 1080p, disk sharing, torrent, any HTPC tasks, all at the same time, with ease
- 100% passive, the MB, the CPU/GPU, but also the power supply (AC/DC)
- extremely inexpensive, 120$ with a built-in CPU/GPU. With 4GB,
- very low wattage, not only the MB, CPU/GPU, but also the AC/DC adapter
- extremely simple to mount, no pico controller, not CPU to mount,
- worked out of the box with XBMC

Still, there are cons:
- I don't think it's able to manage 4K HD. But when I will need it, I will just buy the 120$ build of this time
- No game, really
- The point is that you don't use a PC power supply but an AC/DC adapter (like a laptop). But it's hard to find a case with no power supply case, so you can't really benefit from a small case