There really isn't such a thing as tuxedos for women. But a regular mens tux from men's wearhouse or jos a banks can be tailored for a female body. My partner bought a jones NY tux from mens wearhouse and had it altered to fit perfectly. The females in the wedding party rented tuxes also, and they fit great.
Websites/blogs where our wedding has been featured:
Mens Wearhouse is FABULOUS! My good friend is a "big guy" and he got an amazing tux at a GREAT price from Mens Wearhouse last year. I would probably suggest that you take it to a seamstress/tailor that specializes in womens alterations, though- just so it fits right on your big day. GOOD LUCK!!!
Re: plus size tuxedos
Websites/blogs where our wedding has been featured:
http://www.dapperq.com/2013/11/a-very-dapper-wedding/
http://www.onabicyclebuiltfortwo.com/2013/10/wedding-christina-g.html
http://4realequalityweddings.com/2014/05/16/g-christina/