Assuming that requestScope.importMe is expecting a path to a JSP file
@BalusC is quite clever, and probably answers the question.
However, to be complete, nothing in the standard JSTL will do what you want, but you can certainly create your own EL functions that you can use to do the check. Obviously you'll need to write Java for it, but it's not inline within your JSPs.
The J2EE 1.4 Tutorial has a section on creating your own EL functions.