Kindle was designed to do a completely different job. It uses a specialized screen -- I think it's ePaper, or something similar, based on some work from MIT a few years back -- that's designed to make the text as easy to read as a printed book.
AFAIK, there's no color support on that kind of screen technology yet, or if there is, it's prohibitively expensive.
Correct. That screen utilizes eInk (ePaper, whatever currently the hype word is for it). The main idea behind this technology is readability and minimal energy consumption. Next generation of this technology will probably be OLED (Organic Light Emitting Diode) with which it will be possible to have thin and colorful displays. Sony has developed interesting prototypes which you can see e.g. here. (http://jp.youtube.com/watch?v=NcAm3KihFho)
AFAIK, there's no color support on that kind of screen technology yet, or if there is, it's prohibitively expensive.