There is no way to do that with the production player in the wild.
It might be possible for you to use a debugger player and test the app in a
couple of scenarios, but the user might use the app in some other way and
then it might not unload.
Are there any samples on how to accomplish this on debug player?
I don't know of any examples. It may not even be possible. I would try
using the flash.sampler.* APIs to capture all allocations around the time
the SWF loads and see if you can figure out which one represents the main
class or static vars in the SWFs classes, then continue track samples and
see if you get a delete for those allocations.