What about an older, non-suspension mountain bike? You could put a riser bar on to be more upright and accommodate that growing belly. Or, if you wanted to spring for something newer/nicer, a Surly Troll with a riser stem/bar. Slick tires can be put on for street riding. Good luck, and congratulations on the coming new addition! Six kids--wow! I give you props for being able to manage such a big family and stay sane, not sure I would be able to do that.