Hi Jam,
DCM has staffer, Rangerhouse, who purchased an expensive but perfect machine for sure projects.
You can see it at the start of this topic on our forum -
http://digitalcomicmuseum.com/forum/index.php/topic,4081.0.htmlThat doesn't help you (unless you'd like to send your books to RH for scanning, many have) but it does show that such machines do exist. If you live in the Washington area the Library of Congress has an onsite scanner that is somewhat the same but warning, the colour calibration can be off with theirs.
For home scanning there are some machines that have their scan beds flush with the end of the glass allowing you to put a book on an over at the centre gutter. Sorry, I don't have specifics.
Perhaps some others out there could make some suggestions.
Good luck on this. Preserving these books before time takes them away forever is a noble quest.
-Yoc