In general I think it's a great idea to have XBMC run on the TV directly instead of having a external box. The Samsung TV's (and LG, and probably others) run Linux already, so it's not completely out of the question. It would require some serious hacking of the TV firmware, which is a difficult and potentially expensive endeavor - but pretty cool.
Specifically you are asking for a XBMC app that runs within the existing TV software framework. I suppose that would be possible - but it would probably be less of an XBMC port, and more of a XBMC style interface.
We are already seeing TV's with HTPC functionality (apps for Netflix, Hulu, weather, etc.) so I think it's a matter of time before some manufacturers partner up and include Boxee/Plex/GoogleTV/XBMC inside their TV firmware.
Personally, all I want is a shell prompt and an SDK, but I am not holding my breath for that