I would love to see a bio. from Don as well as Joe and Tim. However, based on Don's actions after he cooperated with Eliot for the re-issue of TTL, I'm not sure who he would trust to work with him on his memoirs.
When Glenn was on the Tavis Smiley show in 2012, he said he had an "outline" he had drawn up. I would not be surprised if he got no further than that as they toured for two years and then he got sick. You would think that as big a group the Eagles are that someone could write a book where the information is correct and we could have more insight into the working of the band and their music. I guess I shouldn't hold my breath on it.