I think that part of the shortage is related to the shutting down of the factory in Finland, as Coreldan was saying, and due to the demand in other parts of the world.
I'm assuming most people here are American, correct me if I'm wrong, and as such, we have an Americentric POV. The US is hardly a large market compared to other parts of the world, and we certainly don't have the growth of other emerging economies. It makes more sense for them to establish their brand, and grab marketshare, in India, China, and Europe as a whole.
So, I might expect Nokia to route a majority of their production towards the other markets, and let the US market buy whatever is available. That might sound unfair to some of you, but it's just the economics of the matter. Even if you say that the average person in India or China can't afford a 920, the average person in Europe certainly can. And even if they are in a recession, Americans seemed to have no problems buying iPhones, so what's stopping a European from buying a 920?
According to the 2011 census, Europe has a population of 739,165,030. The US has 311,591,917 people, that's half the number of Europe. India? 1,241,491,960 people. That's 4 times the size of the US. China? 1,344,130,000 people. That's a combined 8 times more than the US.
Comscore has guessed that there is a smartphone penetration of 47% in the US. So that leaves half of the market for easy sales, being optimistic of course. India's penetration? 2.5%. China apparently has a 33% penetration rate (I don't know how reliable that figure is..). That's a lot more potential customers in those markets.
My exact numbers may be off, but the concept holds true regardless. I don't know, I could be completely wrong, but it seems reasonable to me. It also seems like a smart move. I don't know about China, but Nokia has a strong brand presence in India. Their Asha phones are doing really well there. Also, hopefully, their new plant in Vietnam becomes operational earlier in 2013 than later. They said it would be open in early 2013. I say that window gives them anywhere from January to May. January would be amazing, but I think March is more realistic.