EBook designed as structured HyperText to make it easy to read at varying levels of detail. You start with a summary (Thin Book?), read a bit more from the chapters that sound promising, jump into a section that has a good case study, jump over to a related section referenced in the study, etc.
HyperScope could probably do some of this. But a human editor would have to do most of it (meaning write summary hooks differently than they would be written for linear print).
Is marrying it to Social Software part of this? Or related-but-different?
Annotation Systems for it?
Virtual Community around it?
How integrate with other books/communities?