GBPVR & The Popcorn Hour
Sub has been pretty damn near legendary of his support in capture cards (including one of the first to support HD-PVR) and extenders such as Hauppauge's MVP. He has taken this skill and extended this to the Popcorn Hour Extender. In this case, the Popcorn Hour acts as a GB-PVR client\extender and will stream most anything you throw at it including high bit rate .mkv files. Between the GBPVR client and Popcorn Hour's community plugins you should have no problem finding the right tweaks.