In the States, no. All gi are sold as if for a man, no modesty ties as I've seen on women visiting from Japan. We are left to do it ourselves and most don't, opting to wear t-shirt underneath instead. Me, I don't like having extra layers n warm weather so always add ties as part of my routine dogi modifications.
The t-shirt under dogi is not an alternative to the "modesty string" -- women do that anyway. And men too, in winter when it is cold.
Personally, I would not mind the ladies being naked under the gi, but frankly, I think that could get a bit distracting. :-)