Here's an interesting analysis from The Online Photographer as to what the price on the eventual Canon 5D "Mark II" will be, taking into consideration that the current model is around $2200 at major retailers.
Price determination of any product is a function of many variables, which are all well covered in TOP's post, which is worth a read from anyone interested. Another variable is the current weakness of the US dollar versus the Japanese Yen (and every other world currency), which means that the Japanese companies will have to increase their prices to make up for the difference.
TOP's Future Cost of the New 5D?