The architecture of the LOCKSS system may be a useful guide, but LOCKSS currently relys on each participating institution "owning" a copy of the item. This is most useful for electronic journals.
Portico is a preservation archive for e-journals, based on Documentum. They perform extensive validation before accepting data into their repository.
Meet with the HPSS people to find out about their long-term plans and how best to store files. Can we
eventually store lots of small files (page images)