HI,
The goal of making a federated repository all access in one place in Moodle and "hopefully" in accordance to Moodle's roadmap for repository API is the work I've been pusuing. See:
http://moodle.org/mod/forum/discuss.php?d=43689
The initial intended application is for electronic portfolios, which you may well knows needs access to a federated repository for it to function well. See:
http://moodle.org/mod/forum/discuss.php?d=43813
Have a read of both and tell me if my work interest you given the progress I have made.
Thanks,
Thanh.