The actual game like playable landscape ends pretty quickly and I would imagine in the case of the mountains that it ends very soon after going over the other side. Sooner than it would in oblivion.
As I also posted over there - I don't think that if more provinces are added that these LOD are even desirable ... they aren't quality enough. new ones would have to be made. My hopes is that a lot of what Onra did is portable.
Just wanted to confirm and throw my two cents in that yes, the playable area ends extremely early. Oblivion had a decent chunk after the borders to 'explore', whereas Skyrim ends nearly immediately past the mountain summit.
If Onra's work is portable, and my god am I praying that it is, that would lighten a
lot of the load on modding new provinces, wouldn't it?
With so many new faces on the forums and possible new modders, it seems that it would be far more likely of finishing a new province in Skyrim than it was in Oblivion if Onra's heightmaps were able to be ported over to Skyrim; It would be a matter of populating the area (Which may or may not be easier with the new CK), filling in the landscape, and making the areas feel alive, no?
Either way, very much looking forward to the CK and what will be possible with it.