Here's a thought: I tried installing MySQL unsuccessfully (too many problems to sort through) and had to give up. If you are still considering a commercial release, maybe you could have a non-MySQL freeware release? This would accomplish several things. First, it would save the most powerful version for the paying users. Just as importantly, it would open up a wonderful program to the widest number of people (I think the percentage of people with SQL available is currently pretty low). Once they've seen the features and are hooked on it, it would be natural to try and upgrade to the SQL database. As it stands now, I can't even set up the program to see if I'm happy with all the administrative and formatting features.
I would definitely rather see you go this way than to offer a watered-down version that just frustrates and tempts you into considering the commercial release! By the way, I'm very impressed that you would throw these thoughts out to the users for consideration. Nice gesture.
Dan