I have the same problem with my mare Misty. I used to have a gelding that was really studdy and actually by some strange sort of luck managed to stick two mares. Since then she has gotten worse and we are starting to wonder if by some impossible chance she might be prego.
It's possible she is pregnant. Sometimes a teste will be up inside and get missed by a vet. But it's more likely the gelding has enough natural testosterone he can still get it up. That's what my vet says is actually going on and there's no such thing as proud cut.
A little late in here, but why do dried raspberry leaves work? What does it physiologically do to the horse to calm it down? It seems like an odd remedy, but I've heard it works wonders (as the members before have pointed out).
One thing that always worries me about home remedies is that if they work, then there is a reason. If they change hormones for the better, then how do we know that they are safe? Maybe they have a high level of estrogen? Then can't that be harmful?