It's hard to think of a situation in which you would really want to do this. Variable names are just something for the code or the coder to use to create the program. A GUI is for a user who should be abstracted away from anything involving variable names. Usually you would just put things on the GUI that make sense to a user and then under the GUI you interpret those as necessary for the program. In a normal usage a user of a GUI shouldn't know what variables are in the base workspace because the GUI uses its own hidden workspace.
You can use horrible constructs involving eval to do this, but they are so unpleasant I have purposely never learned the syntax to do so, but no doubt someone will provide an answer along those lines soon enough.
