Development One in Australia sell a product called the Home Media Centre that uses MythTV (with some custom modifications / modules?) as its core.
OpenMedia in New Zealand have a product called myPVR based on MythTV that was developed for the NZ Market.
Better Access in Australia have sell HTPCs that are designed for use with Knoppmyth.
Chimera Media Center : New Italian HTPC based on MythTV
X-es Media Center : Dutch HTPC based on MythTV