Area portals are a good way to do it, and it seems most posters here are forgetting that if a feature is hardware demanding, there is usually an option to switch it off. There is no need to render all objects on the other side of the window, as a lot can be removed by occlusion culling, and you can't see fine detail through a window that isn't smooth, or one that is colored. It would be very nice to see this as an (optional) feature, and thoroughly optimized by Bethesda as opposed to a modder only having his spare time to work on the project - making it much less resource demanding.

I could care less.

http://www.youtube.com/watch?v=om7O0MFkmpw

Just because one game can do it, doesn't mean TES can. The scope of TES is more than any game on the market, even Fable. I'm sure they would do it if they could, they can't. I'm fine with it, as there are many more important things that I'm concerned with and none of them have to do with graphics or animations.

That's sad.. I hate loading in and out of buildings. Makes thieving slightly stupid when you don't have to worry about people on the outside being able to see, stop or catch you. The other stupid thing that always seems to happen with interior cells is that they don't match the architecture or size of the building on the outside. The size of the towns will really determine how mad this makes me. If the towns are as populated, big and detailed as lets say Assassins Creed.. then I won't mind interior loading cells. If the towns are only as big as say a game like Gothic 3, RDR or Oblivion then I'm going to be slightly upset. Gothic had huge towns.. and lots of interactive gear.. Not as much as morrowind and oblivion but you'd think they would have tried to have open buildings in skyrim

I've said it thrice, and I'll say it again: portals.

heres an idea -

what if when you open a door, it swings open and while its doing that, it loads the basic meshes/textures for the immediate room, and continuously loads and updates the environment depending on what your looking at.

this way, when you have many buildings, the things that are inside them aren't actually loaded until you opened the door, would wouldnt cost much CPU because you can only ever have a around 1 room fully loaded

And I'll say it again, just because if might work in one game doesn't mean it will work in another game with another game engine. Unless you are a programmer and have used the engine they are using you can't say for certain that it will work. This same thing was asked for in Morrowind and in Oblivion. I'm sure every time they make a TES game they try and make this work.

It's not a big deal really.

But, it's within the capabilities the engine ran on. In fact, I've been told Reneer is even making excellent progress on a mod to accomplish this in Oblivion... It definitely is possible.

Well, speaking as a (at least attempting) programmer, your engine does what you want your [censored] engine to do. They're built, not born, you decide what you want and then you make it happen, you don't take what you're given and work with that.
If bethesda decided, as a purely objective choice, to implement some form of seeing through windows, whether it be dynamic loading of interiors when necessary or a deferred rendering like portals, then it is in. If they decided against it, because they didn't want it, not because they didn't think it could be done (because it can, and they're capable), then it is not in.