You might find it useful to examine how this is handled in Sugar education software. We provide software for portfolio building, integrating a variety of materials into a sequential presentation on a specific topic. Students can then reuse those materials in other presentations on topics that arise from the first one. Thus a child can assemble or create materials relating to the child's environment (home, school, culture, country...) or to a school subject (a question in science, a piece of music, a work of art or literature...) and then take an unforeseen angle into a new portfolio, perhaps drawing on several earlier works, just as is done in grown-up art, science, literature, business...
These varied portfolios are automatically stored in a Journal, along with sessions from individual software activities in any subject area. The Journal supports sorting and searching on topic names, descriptions, tags, date and time, the software used to create a session, document types, the names of other children who collaborated in a session, and so on.
Sugar is available for almost any computer, either natively in Linux or as Sugar on a Stick (USB thumb drive).
I would be happy to provide more information if you would like.