Just found out about MakeHuman, a slider-based parametric modeller in the Poser/Daz/Facegen tradition. The interesting bit is that this is open sourced and written in Python, so it should be extensible.
http://techartsurvival.blogspot.com/2014/03/sliders.html
http://www.makehuman.org/
Like most of these guys, it’s not ‘one button art’ but it’s a good starting spot - and the topo looks good at first glance, though I haven’t poked at it much yet.