Depending on what you're looking for, a lot of the ladies over at 2KG Presents will be able to satisfy your needs! Stella, Ruby, and Elle are all tall, and they all have particularly lovely asses. All three have also worked as professional dommes in the past.  

I also offer ass worship like you mentioned, and my body is hot if you think bbw women are sexy.

Most classical mistresses in Chicago don't allow for intimate body worship, so you're better off looking for escorts who emphasize bdsm/fetish/kink play