I'm a big fan of New Vegas hardcoe mode and I hope Skyrim incorporates some form of hunger/thirst/sleep deprivation, as an optional mode at least.

Since the Bethesda people have responded to any questions regarding hardcoe mode in a vague way, rather than saying "No, it's not going to be in Skyrim," my educated guess would be that this is something they are playing around with but haven't decided whether it will make it into the final game.

^This.

I'm lazy, I know

Ah! That could work. However this would require that you only get thirsty in somewhat real time. If that weren't the case, then I fear there simply wouldn't be enough sources of water in the world. There is bound to be large areas in the game without a single puddle. Certain caves will also lack a water source. If you get dehydrated at a rapid rate, I fear hunting for a water source could really hinder the experience.

However, some people may love having to look for a water source. So I can see a mode being implemented where you would need to look for water/ask for some in towns and eat regularly. For the other reasons I mentioned, I still don't see a "limb damage" system working, but who knows. Also, a big point of Fallout: NV that I loved was that in hardcoe mode you did not die faster and enemies were not tougher. I think that should be all on the difficulty level and separate from a hardcoe mode.

So while I don't think it would be as extensive as Fallout's hardcoe mode, something could be implemented for food & drink.