Turns out that there is some historical truth to the Gladiatrix comic. I read a recent article about a statue found of a bare breasted female gladiator that fought in the Roman Empire. While rare, these female gladiators did exist and fought for the amusement and sexual arousal of the male audience. As slaves, they were also used sexually by their masters.
http://news.yahoo.com/rare-ancient-stat ... 08435.html
A quote from the article: "In the Roman mind, there would have [been] certain associations with the sexual availability of slaves,” McCullough said. "Slaves were sort of expected to be sexually available to anyone at anytime, especially their masters." "