No news on whether Matt's final story is getting an individual release, but a set containing the episode plus all of his other Christmas specials has been announced for release in January:
Extras so far include a behind the scenes of TTOTD, a Farewell to Matt doco & Tales from the TARDIS.
Quite why they are going down this route when most people already have the Xmas eps in their series boxsets I don't know, esp as rumours abound that TTDOTD is being released on its own in the US. As it stands at present though, this is the only way UK fans will be able to get Matt's final story. More news as & when.