I can understand a higher cost, since it is designed to act as a replacement for a laptop, but it is not a true replacement. I love my Photon, but I could get a laptop for the same price, which will obviously surpass the capabilities of my phone.
I think that the laptop dock would be reasonably price in the 200-300 range. It won't be a huge seller, but if you buy a motorola keyboard and HD dock, you are in the $150 range, then add in a screen, and the portability factor, I would think that is fair.
However, I'm not buying one...