At least that's what I have heard from parishioners-it's probably not official policy, but rather a holdover from the "old days". I ain't SBC, so I shouldn't even be speculating on it, eh?
I’m SBC and the reason that there aren’t women preachers in SBC is that there are scriptures against it (I could look them up, but I’m lazy). However, there are no scriptures against women holding public office.
As for the pants issue, it really depends on where you are. I wouldn’t dare wear pants to church in the south! I don’t know if things have changed, but when I was growing up in AR you either wore a suit and tie or a nice Sunday dress to church. Here in the North West you can pretty much wear anything (within reason) to church and no one really cares. I usually wear nice jeans and a sweater in the winter.