I heard that eLumen 3 has some kind of portfolio built in. I think Brian Donahue-Lynch might have said it. What you're talking about is augmenting the eLumen interface. I think of a mashup as a separate application which combines data sources to produce some desirable output.
So, for example, we could write a php application which reads in the ePortfolio publications of student work(IF it's a standard database system and they give us read access from outside the system), then reads in all the scores, and allows the user to create a link between a score and a piece of work. Sounds wonderful at the outset, but it'd be quite a trick to actually use, since it jumps out of the workflow of the eLumen scoring system and puts you in another application.
Getting back to what i was saying - what you want, i think, needs to be a feature request to eLumen for one of two things:
a) request fields in the rubric which ties the rubric to a selected work in ePortfolio, or
b) request that a hook API be added to eLumen so that hooks could be written which add fields to the view, processes the connection data at the model level, and gathers data from eP at the controller level to get it ready for the view. (this would be ideal)
Phorum (the forum software we're running on this site) makes extensive use of hooks, which can do everything from add new fields to the post form to database maintenance.
I'll see if Ken C. knows anything about the openness of the e-Portfolio database.
James Revillini
eLumen Admin / Research Specialist / Webmaster
Tunxis CC