Another question - what's so different about the generations that would keep Amazon from backporting features? The K1 is an obvious dead end, with the whole wheel to joystick UI change. Is there a large hardware difference between K2 and K3 that keeps Amazon from just delivering a universal firmware (give or take the cellular bits)?
I would love to have the improved PDF support on my KDX US wireless. Porting the Webkit browser doesn't worry me so much.