[mclazarus]

I know it is clearly not what you want to hear, but I would highly recommend against that. Besides the technical reasons of clogging up your DB with reference material. I don't know about you but I have hundreds to thousands of MB of digital reference material, PDFs images, diagrams, presentations, etc. This will just serve to slow down OF something you need to work as fast as you can think.

Asside from the obvious a single level hierarchy of folders that you sync using unison, iDisk syncing, or some collection of scripts to an iDisk or other webdav or other kind of server. There are other tools out there designed to handle exactly this DevonThink and Yojimbo and probably others.

I think you need to use the proper medium to store your reference material. If you try and cram it into OF it will just blend in with your tasks. You will need to mentally descriminate between actionable things and reference material. David Allen does a good job describing this type of thing when talking about the email inbox or refridgerator doors. To the extent your OF DB has as many entries as mine does you will need to use searching at times to locate stuff. The lost time and brain cycles to sorting out reference from actionable things is probably not worth having it in one single system.