You have to look at what you are getting with these guns. They (especially the Norwegian) are an X-5 only in that they use an X-5 frame. They do not have any of the other features of the regular X-5 pistols that make them better than the standard Sig lineup, perhaps most importantly they don't have the heavy match fitted barrel.
Anything extra you would pay for one of these over a P226 stainless Elite or similar is only getting you a slightly higher undercut under the trigger guard on the frame. You might get a slightly tighter slide-to-frame fit, thats hard to tell. It appears you may also get the nicer Combat style takedown lever (not that almost anyone really needs one). Hopefully you could get the generally better German hammer that come in the X-5 Allaround, but you will also probably get the new sears they are using. They are using a slightly different sear on the current German production guns to lighten the SA pull (the change to lighten the pull is done in a "bad" way IMO) and they are almost all hand fitted to some extent; I haven't found a single one yet the the German "gunsmiths" haven't screwed up and polished it crooked.
So, if you can get one for $1100 thats probably a decent deal if you would have paid full retail for a P226 Elite; but $1800? Theres no way to my mind it is worth that.