At Arlington we had a joint effort of 26 high school and middle school math teachers. We wrote an E-text, comprised of apr. 120 lessons and associated homeworks that we are field testing this year.
It took the better part of last year to write this and we are still editting it. We plan to eventually copyright it and then give it away for free to any district that wants to use it.
Hope this helps. We are so far very pleased with the text, especially how we have incorporated the graphing calculator. We are also happy to not have spent a lot of money on texts that we aren't happy with.