I know this thread is a bit old, but I was wondering if time and development had now given another outcome to this question.
I have a PS50B650 and a PS50C7000 and would love to be able to run a MythTV Front end directly on the TV.
I ask the question again as I have found this : http://sourceforge.net/p/smartmythtv/wiki/Home
Where steffen managed to do exactly that, however, I think it's on more recent models. I have asked the compatibility question on his forum but haven't heard anything yet.