Writing a graphics card driver is fun once in a while. You learn a lot and it is not so difficult as one would think, at least not if you plan it in a structured way. It takes a lot of imagination for the developer to write a driver, because it is difficult to test all combinations.

Grabbing and understanding the specs 'as such' is a real challenge sometimes. Even when all is documented it still takes a lot of time to solve some puzzles. Probably it is more important to get the card out first than making some good documentation.

To summarize: If you love a challenge you should consider developing a BeOS graphic driver. You can get far with the right documentation and specs you find in this guide. At least the 'step plan' is a good tool to follow. But, still, it is a great challenge...