You can either write your own Interceptor (or base it from the default one), or if it just a matter of "look" use a different theme for your other portals.
Thanks for the response. Using a theme won't work because its the actual structure of the HTML that is generated not just the style of it. I can certainly copy and modify the default interceptor. One question I had though is that if I do that, won't that configure the way the tabs are generated for the whole portal? This would mean if I want to have differnt navigation components for different portals, I can't do that.