well, you definately have a niche forum, so I think the best way to determine how to make money is to decide what your target users would be willing to pay for. I mean, if you came to your own site as an active user, what is one thing you'd LOVE to have, and wouldn't mind throwingi a few bucks to have?
I can't answer that question, I've never even used Filemaker
But use my site for example... mainly it's the photo gallery. Jeep users take tons of pics of their vehicles, off-roading trips, etc. Usually, these users have no place to upload them, or if they do, it's with imagestation or a similar service, where they can't link to their photos in their posts. So.. by giving people who donate money to the site added photo space (5, 10, 20 MB) a lot of people are willing to pay to make their own galleries on a website they use everyday rather than just some 3rd party system.
So that's my real niche.. I'm not sure what yours would be, but think about that, and see if there is a really cool feature, or addon you might put in place to only allow paying members to use. A little bit goes a long way...
