5D2 in Italy was a pain in the ass to get. Announced sept 2008, we had very limited supply till feb/march 2009.
Then more or less ok till june 2009 then camera disappeared again just before summer hot season.
But this is also a marketing gimmick and not only the capacity to produce or not. Marketers love to have people desire something which they can't get. The price and expectation remain high, the perception of the value of the item is at the highest possible point. On the contrary high inventories create low prices and bad feelings into buyers. So be sure that, also with the 5d3, volumes to market will be accurately tweaked by Canon, based on a well tested strategy (and they are masters at it: look at the 5d2 after 3.5 years how many they are still selling)