Is there any commercial off-the-shelf pre-configured small Digital Video Recorder / PVR unit based on Linux, XMLTV, MaxemumTV, MythTV, Freevo?

Is the above programs ready for commercial / general public usage?
Is it easy to use the programs?
Is it possible to use the box with Youtube, Google Video, IPTV etc?
Thank you.

http://xmltv.org/wiki/

http://www.theducpond.com/freevo/

http://allmanj.frlinux.net/drupal/pv...al_first_steps