The same thing was happening with existing Webparts as well, Peter. I did a little more investigation and determined that this is default behavior for Webparts and I instead needed to use Widgets - which I'd formerly not used at all. As I understand them (at least in my current usage), a Widget is nothing more than a Webpart that can only be used in a Webpart Zone specified for Widget use (type Editor, for instance). When used in this way, Webparts (via a Widget) are single-use only and do not automatically transfer their data to each page which uses the same template. So I created a Widget that effectively uses my banner Webpart as-is, modified the Portal Zone Webpart Zone type, and it's now doing exactly what I wanted, that is, allowing me to add a different banner on every page.