I'm more experienced in sound editing (not great but better than most) and this kinda thing always intrigued me...
Anyways, I have a bit of rumor I heard from a fairly reliable source concerning the Holiday Special - apparently Australia's FoxTel (sp?) station had entered into talks with LucasFilms to promote a one-off 30th anniversary airing of the Holiday Special for next year, with the possibility of a new George Lucas chat about the history of the special afterwards.
I'm not really too sure about the truth behind this but as I said the person I heard this from is usually pretty knowledgeable about the Holiday Special
As for if it will be remastered/cleaned up? Can't say, but I'm sure George still has the original negative up there at Skywalker Ranch in the vault