I'd be in at the $50 level. This has needed to be done for some time, and this model seems like a very safe, if slightly more expensive path.
On top of that, I'd be willing to do all the graphic layout production work for the book for free on my own time. I've got over 20 years experience as a professional graphic artist, and have done books as large as 220 pages. It's a lot of work, but I have the time and commitment to d20 Modern to follow through on it.