ENlight has gone and made a SFF PC case, that is essentially shoved into the back of a 19" touchscreen LCD.  They even managed to do it without making it look too ugly.  HEXUS has a full write up of this mATX setup, and found it very flexible.

"It's about time somebody came up with a PC-in-a-monitor solution that was easy to upgrade, so when

ENlight's LCD PC chassis landed in the labs, we were skeptical about the promises on its box, but

we're an equal opportunities bunch and gave it the HEXUS examination."

Here are some more Systems articles from around the web:

  
HTPC

• Shuttle X100HA Small

  Form-Factor PC @ HEXUS

• Thermaltake

  Mozart TX @ techPowerUp!

• SilverStone LC18 HTPC

  Case w/ Touch Screen @ 3dGameMan

• Phylon 7F2WE-1G5 Mini-ITX Mainboard Review @ Epiacenter
• Zalman

  HD160 HTPC Case Review @ MetkuMods