I think making them anatomically proportioned should help with this, in terms of the "nether regions". Considering a Roegadyn will not have the same proportions as a Lalafell. I think having a sliding bar for that would open itself to abuse by players...

I think I can speak for everyone when the thought of having a Lalafell named Buttercup Gumdrops with a thong shouting for everyone to look at his big key, is nightmare fuel.