Hi,
Sorry, there is no Master Web Control in Vs3.5. But thank you very much for your great idea.
In fact, the master page drives from the usercontrol class, when the application excuting, the master page just as a usercontrol on the content page.
So if you want to build some common structure on the pages, you should use the master page instead of so many usercontrols, and you can create more than one master pages in your application, then change the page's master page programmatically, so using master page, it will simplify your task.
Please remember to mark the replies as answers if they help and unmark them if they provide no help.
Yours sincerely,
Amanda Wang
Microsoft Online Community Support