Quick update - got Server 2000 rebuilt and Exchange 2000 on there with Backup Exec 10d. I've inventoried and catalogued the relevant tapes and have got the years old mailboxes back off. This flies in the face of the advice our support company gave us, which was that we needed the exact versions of all the service packs, hotfixes and patches, a full AD restore and countless other stumbling blocks along the way. 'Course I could've stumbled on the exact config in the build I made, but I don't believe I'm that lucky. However, we have a few happy members of staff. :)

Thanks for the help guys.