I agree with the other posters that you can find a good 30 ft. boat for under $20K. Heck I'll sell you my 1981 Hunter 30 for way less than that. I also strongly urge you to have any boat you're interested in professionally surveyed. Good luck with your search.
Now let me change gears for a minute.
After reading your posts I wonder if sailing is something your wife will really take to, even after the baby is born. If a powerboat wake freaks her out, or 3foot choppy waves make her uncomfortable, maybe boating isn't her thing. Heck, boats rock and roll all the time. If you're building your boat-buying decision around making this a family activity, you may be in for a big and costly disappointment.
IMHO nothing is going to contribute faster to marital discord than you spending $20K on a boat she's not comfortable aboard, then using it to spend weekends cruising around the bay by yourself or with friends, while she's left at home watching the baby. This is a recipe for disaster and I've got the scars to prove it.
Anyway, it sounds as if you have more to decide than what boat to buy.
P.S. My scars came from the time I bought a Honda Goldwing. Mama never did ride with me.