A new project that just popped up on CodePlex is a SharePoint Document Version Exporter web part. Here is information from the author on it:
The Sharepoint Document Version History Exporter (better name pending) is a WSSv3/MOSS2007 feature that allows you to import Sharepoint controlled version history into your MS Office documents.
Currently, the feature updates extra columns in document libraries with 6 version information sets - 1 for the current working version and 5 previous versions. The version information stored is the version number, version author and comments.
This information can then be accessed inside the MS Office document via the document properties. It can then be added into the document as fields, and a small macro can be written to update the fields automatically whenever the document is opened.
CodePlex Link
