Hello Cabbage -
Your only other option to 'unload all' would be to set the per-step load and unload options via right-clicking on the step and selecting Properties.
On the step properties window, examine the tab for Run Options. Here you could tell just one step to unload its module after execution so that you can run a test, edit the VI, and run another test, etc (after you're done debugging you can set it back to its original unload setting). Maybe this will help.
Regards,
Elaine R.
National Instruments
http://www.ni.com/support