Ah, the Thonk book...
The first time I met Michael was at an in-store appearance before an evening show while he was touring to support Thonk. Wow, was it really 12 years ago? Yikes! Anyways, I asked him if he was going to be putting out a book for the album, and he pulled out a notebook to show me his handwritten transcriptions, then explained how he decided to notate the hipshot and bridge tuning changes since there was no standard notation for that kind of thing.

I got to talk to him for about a half hour, then helped him carry his gear out of the store, and he got me in early for soundcheck and a front-and-center seat. Oh yeah, and an on-stage appearance to hold Bub during "My Favorite Moons". Good times.
Sorry, aside from the suggestion of checking Ebay, I don't have any other suggestions. I just felt like sharing this fond memory with the group since the Thonk book was brought up. Good luck in your search for a copy.
-Mike