I disagree.
A friend of mine had no middle name so she made her maiden name her middle name when she got married.
Mostly, I think, because she was her parents' only child.
I don't think you can classify keeping a maiden name as a middle name the same way as keeping a maiden surname or hyphenating. I use my maiden name as my middle name simply because my middle name at birth wasn't one I much cared for... and it was a nice, private way to preserve the connection to my maiden name. Since I generally use just a middle initial (if that) it isn't a big statement making issue. Actually, as another poster noted, I think it is very traditional for a woman to keep her maiden name as a middle name. Is it that different from using a mother's maiden name as her son's middle name? That's pretty common... especially among presidents. JFK, LBJ, I think Ronald Reagan.... Since a middle name has little legal signficance, I don't see any big deal about it, nor does my husband.
That's what I did -- and you couldn't find anyone more thrilled with being a Mrs. than me.
My other pet peeve is when adults ask that our children call them "Miss Patty" or "Mr. Pete." I tell them that we are a "Mr and Mrs" family and that we are teaching our children to show respect to adults by using their surnames. I do not bow to the inevitable petty protest that: "Mrs. So-and-so is my mother-in-law."
We've converted our immediate section of the street and are on to the rest of the neighborhood!