Here's a proof of concept patch that adds a 'fullstack' option to print_exception.  The problem with this concept is what happens when you use it on an exception caught at the top level of a module.  I'm not entirely clear on why tracebacks work the way they do, so I don't know how to fix that case (it's also late, maybe in the morning I'll be able to figure it out :)

Writing unit tests for this may also be a bit tricky.

I'm raising the priority to normal because I think this would be really useful for logging, as pointed out by Thomas.