My hands aren't exceptionally small for a woman (size 7 gloves), but I definitely prefer Campy Ergopower shifting to Shimano STI. Bar-ends are also nice for those with small hands. With those, size doesn't matter. However, there's still the braking issue there.

But, if you have a Shimano bike, the Campy option would be way too pricy - I'd just try to find the Ultegra short-reach levers as others have suggested.

Good luck!

Emily