If you were to have a 'lift the flap' type book that you wanted to digitize, for web display and use, what technology would you use for markup and display?

Visually I like the Internet Archive BookReader ( http://openlibrary.org/dev/docs/bookreader ), which says it can do 'foldouts', thought I haven't found an example of HOW to do that ... nor exactly what the metadata schema is.