A "switch case" tag - Maybe Tedd knows???
So, there should be a ActionForm property that would be populated (automatically) by the controller. A helper property could then look at the property and output whatever it is you need here.
In a Model 2/MVC application, the pages should be glofified mail-merge jobs. If you feel the need for a swtich statement or anything like that, you are drifting back toward a Model 1 application.
As mentioned, the new JSTL taglib does have many features appropriate for Model 1 applications. If you are making use of the JSTL, see also the new EL taglib in Struts beta 3 and the nightly build.