Hi Buzz, unlikely you will find anything straight off the shelf that will fit but most guns can be modified to suit so I don't think you have to go to expense of a custom stock.
As Mike says, first port of call should be an experienced gun fitter for females. Stock shapes for women tend to have a little more cast (or pushed out toe)and quite a reduced length in toe to fit their frame. As you have pointed out, females are different from us in the chest region and the stock has to accommodate the extra bits they have!
For the first timer female I would recommend an Italian 20 gauge over & under, not too expensive on the wallet, slender enough in the grip for small hands and can be bent and cut down to fit easily (at 5ft 2in, a stock length in region 13 1/4in to mid depending on length of neck and arms too). Coupled with a good pad on the end and some lower velocity loads, this is a good place to start.
One final thing, more than likely your significant other is left eye dominate, most females are, so beware of this but a good fitter will pick this up.
