Have you tried biting her back? I'm serious.

I have a girl who occasionally bites too hard when I'm holding her, and
when she does I bite the scruff of her neck and tell her "Too hard!".
Surprises the heck out of her, but she backs off.

Now, she IS a biter: it seems to be her preferred method of
communicating, but usually it's not too hard, and as a guy with thick
skin I can take it. We 'fight' all the time and both have a lot of
fun, but still she bites.

Sounds to me like she's still young and skittish, so you need to be
calm, reassuring but still set limits; otherwise she may grow into the
habit permanently. Don't be afraid of her (That's what she wants!) and
if she doesn't want to be held, don't hold her. Pick her up now and
then in one hand, give her a treat with the other and set her back
down. That way she'll learn to assoociate being held with goodies and
not danger.

[Posted in FML 5695]