http://mpc-hc.sourceforge.net/ does, although I have found some H264 broadcast streams that don't work. I don't have a clue if it's the player, DXVA, the drivers or UVD on my card that's the problem. Most H264 seems to work - the ones that didn't were 1088x1920 so maybe that confused things.
As for OSS, UVD may be out of question, due to HDCP, but the devs have already said that there is enough info out for 3D engine GPU assisted decoding, just no one has written it yet.
In fact if there are UVD limitations to precise stream types, using the 3D engine may end up being a better and more flexible solution.