Ok, how about this:
3 locations in different areas:
* Locked storage room for paper(tape) storage
* Virtual Machine image off-site
* Local office file server
*) Scan and process documents in the local office storing the documents on the local server.
*) Make sure your local and remote server are running an encrypted filesystem on top of a RAID with mirroring.
*) Set up an rsync cron job to sync your virtual machine to the local office fileserver
*) Then archive the paper documents daily or weekly or monthy (you could even in parallel do tape backups)
This sort of set up would not be expensive for a small amount of storage (i.e. office) and will cover you on fire protection, original retention, etc.