Gidgreen, I think what you've done with the software so far is extraordinary. I fully support the potential for a future (paid) version - I can only imagine what that would allow you to do with the software.
I'm pretty sure when researching what q&a software to use I came across a couple of gpl/mit-type licensed editions. As it happened, they had nothing on q2a.
Please don't fix anything that isn't broken.