Mai Yamane - lead singer of Yoko Kanno and the Seatbelts
Linda Perry - more known with the 4 non blondes
Johnette Napolitano - of Concrete Blonde
Andrea Echeverri - of Aterciopelados
Miley Cyrus - ever chided for her whiskey voice
Mary Chapin Carpenter - She really has a more neutral singing voice to me, lower than many of her contemporaries.
Liz Phair -- similar to mcc
Amy Ray - of the Indigo Girls
k.d. lang
Gail Ann Dorsey
Sass Jordan -- noticeable on the Rats album particularly...
Lisa Gerrard -- most known through Dead Can Dance, but there's quite a bit of range there
an endless amount of blues, jazz, old country (early texmex had a disproportionate number too) performers ... a handful of musical/operatic singers that are more known for it plus for more specifically the celebration more than the novelty of crossing the gender barrier in other areas -- though some might look at metal (a few known figures, but there are those that sing at higher pitch but also vox, growl, showing off their metal bravado/authenticity) and punk as well.