You can easily do this with FMP 10. If you use an earlier version of FMP, you can do something very similar to what you describe.
If you have FMP 10:
Define a drop down or pop-up menu that lists your layouts from a global text field.
Define a script.
Go to Layout [table :: gTextField] //Layout name by calculation option
Return to the layout and define a script trigger to perfom this script when the field is exited (drop down lists) or changed (Pop-up menus).
Note: If you don't put the actualy layout names in your drop down then you have to write a more sophisticated script in order to do this but it still can be done.