"YOU ALL break down a discussion about everything else in the world." 

That does to happen on occasion as in real life.

The problem with a prop is that I don't think you're ever going to get anything realistic that has to interact with the existing hip geometry.

Daz' former partners in crime at Zygote aka 3DScience.com will be happy to sell or make you any detailed anatomical model you desire - at a price that the Gambino Family would consider extortionate.

Regarding post work, someone at renderotica had a package, "flanges" something that addressed the exact issue though I don't recall if it covered the posterior as well as the anterior orifice. I'll leave it at that so as not to be further responsible.

"Democracy is a pathetic belief in the collective wisdom of individual ignorance." - H. L. Mencken