Upon further reading, I see that the IMS specs are pretty detailed. There's a tiny little section of the data model devoted to scores; the rest has to do with representing the assessee's responses to questions.
Stepping back for a moment, I think the challenges are to figure out a) the data model and b) what API calls to expose. Acknowledging the simplest case solution ("create table object_grades (object_id references acs_objects, grade integer)") it would seem reasonable to look to organizations like IMS and SCORM, who have done all kinds of research to figure out what educators want, and build on their most relevant findings.
Michael, I haven't looked at the SCORM stuff yet. Care to make any comments about how to best use IMS versus (or as a complement to) SCORM?
