Adding controls via xml document

[modularbeing]

I have a template aspx that is configured by an XML document and I will be hosting a bunch of user controls on this page. I would like to define which controls are added to the page via the XML document as it changes depending on who accesses the site. I am unsure of how I could add them to the site without a select case for every type of control I might use in the XML configuration. I dont mind doing the select case but it seems like there would be a better way of doing it. any ideas?