The other thing that has changed, and that people are probably overlooking, is that the US Dollar has weakened considerably since the first two tablets were released. Prices for lots of imported things are going up. (It is speculated that this is one of the reasons why the $199 price tag for the soon-to-be-released Asus eee PC has risen to $299 and $399.)

Certainly the slideout keyboard and GPS also add substantial cost to the manufacturing unit cost, but that probably only contributes partially to the price differential between original launch prices for 770, N800, and the new N810.