OK, this thread made me realize that people do not actually care to study the history of things. The folks that do in this thread, wow, you folks are amazing. Part of the problem anymore, and this is too worldwide, is that people forget the history to mold something into their own little thought bubble.
I will admit to liking harem in a fantasy sense, but dear lord, the real ones are some craziness that would boggle the mind for most people. Then you throw in the tropes, like some have in this thread, which brings in another layer of craziness that needs to be addressed if deciding to put this in a game. I say this because I am writing a game up right now with a more Mongol or Chinese based thought on a harem, but may go Arab. They are not so different, but it is enough to make me get out the books I have not read in years.
That said, this thread does have some folks we should all aspire to in having some actual sense in learning about a topic to understand it.