Regarding lightsabers: Whoever wrote the Star Wars database article is a fluff writer and knows nothing of the "actual" science behind the weapon. A lightsaber requires enormous amounts of power, which is why Jedi in the era of the first Sith War (five thousand years before the battle of Yavin) had to plug them into their belts.
A lightsaber is not an LED. An LED, while it emits both light and heat, has almost zero electrical resistance. A lightsaber is a free-formed beam of light. Anything that generates light generates heat. An LED generates heat because it basically sets fire to the electrons (is that the right word?). An LCD television or computer monitor generates heat as well, and all it does is display colored light.
How can a weapon (or device of any sort, for that matter) that generates a length-controlled beam of coherent (tangible, physical, visible, etc) light not generate heat? Light is hot. If I shine my LED flashlight on my wooden desk long enough, the area on which the light falls will heat up.
A lightsaber is essentially a very powerful laser. It absolutely generates heat whenever it is turned on. Saying that it only generates heat when it comes in contact with an object is utterly ridiculous. An electric knife blade only generates heat when it contacts an object, because that's the only time it produces friction (the motor generates heat all the time, but I mean the blade itself).
Anything that is as small as a lightsaber, and has the power output of a lightsaber, generates heat whenever it is turned on. Running wires from one end of a battery, through resistors and then back into the battery generates heat, and that's not producing anything but electrical resistance.
The databank article mis-represents the lightsaber to avoid answering this question: "How can you fight, for any extended period of time, with a giant heat-producing, coherent laser beam two inches from your hand and not smell burnt meat?"
Getting back on topic: Yes, the lightsaber could have made a viable heat source. But what was Han to have done with it? Stick in in the snow? It would melt a hole through snow, ice and bedrock all the way to the planet's core, or at least until it hit something hard enough to stop it, or hot enough to fry it's electronics. Hang it from the ceiling of "the shelter?" Better hope the wind doesn't blow too hard.
I think that the amount of heat the lightsaber passed to the tauntaun corpse, while perhaps measurable, is negligible. It certainly wouldn't have had any notable effect on how long Luke could have survived.
This debate is entirely academic, at any rate, because Luke DID survive, so really the question becomes: how long did it take Han to build the shelter?
I have to go with "several seconds, perhaps an entire minute." To re-iterate a previous comment: I can go to Wal-Mart and buy a tent that unfolds itself in just a few seconds. Then all I have to do is nail it down.
That argument does beg the question: If it only took Han a few seconds to setup the shelter, why bother cutting open the tauntaun? Answer: "Shit happens." Yes, under ideal conditions, it only takes a minute to setup the shelter. But Luke is delirious, probably dehydrated, and all-in-all, in bad shape. If something goes wrong, and it takes longer than planned to build the shelter, Luke will be okay for the few extra minutes Han needs to fix it. If everything does go according to plan, no harm done. Luke is no worse off than he would have been had Han not stuck him in the tauntaun.
"Plan for the worst, hope for the best," my dad always said.
So: How long could Luke survive in a Tauntaun? Who cares? At most, it should have taken Han five or ten minutes to pitch a tent and setup a space heater, even in the middle of a blizzard. If he was doing anything more than pitching a heated tent, he needs to be shot for unnecessarily endangering his friend's life.
If anyone has, in fact, pitched a tent during a blizzard, I will of course defer to their experience, but you can be damn sure I'll be trying it during the next convenient blizzard. Watch this blog for debriefing.