Hi Richard - I checkedd with our support team on your question and here was their reply:
If the Business Portal installations on each web server need to have access to the same Dynamics GP 10.0 databases (DYNAMICS and company(s)), they would need to use the same site collection pointed to the same SQL Server instance and databases as well as content database.
Each web server will have to have its own IIS setup, web services and MOSS 2007 installation along with Business Portal. In SharePoint Central Administration v3, you should see the original site collection already present and connect/install to that.
Please let me know if you have additional questions.
Thanks!