Hi,
I have been working with PP for nearly three years now - and I have utilized most of its functionality thru the projects I have managed - it is really a helpful and useful tool.
However, being a project manager within IT - testing is a big deal and is a very important part of any project. Without a proper tool that allows for test case definition and coordination & measurement of test progress, testing becomes inefficient.
I am happy to contribute with more details ideas if this idea is interesting.