We're looking for an end-to-end document encryption/secure document collab solution for SharePoint 2003 document libraries? ....both for Office and non-Office documents.

We're familiar with Office 2003 IRM (information rights management) and see it as part of the solution (for protecting documents during creation/review/edit cycles) but aren't sure it is the right approach for long-term secure document storage (e.g. long-term = 2, 5, 10, etc. years).

If you are a SharePoint customer, partner or ISV, I would like to hear about your experiences trying to create an end-to-end encryption/secure document collab solution for SharePoint 2003 document libraries.