Someone told me that they did a lot of work in this area and created a
GotDotNet workspace to capture the results. I can never find anything in
the GotDotNet workspaces but he was really proud of his work so I have
to believe that it is there. Unfortunately, I don't have his contact
information.

I was never successful, I don't think Sharepoint SDK allow you to change
this, the only workaround we found was to save the data in one of the
meta-data column and run some SQL Update statement to parse the author
and update the column in the USER_DATA table

This can't be done through the SharePoint object model.

You need to use a tool like the Tzunami Deployer that knows how to reach on under covers to set  the author, creation dates, etc. to the values found in your original documents.

That said, there are some third party tools out there. Check out
Syntergy's products for example:
www.syntergy.com/sharepoint/products/index.html

They have a bulkloader that can maintain the identify of the document's
original author  and the original date of authorship.