i miss the old kickstarter roulette )=....

With regards the 'how long does it take to sculpt these'...the answer is quite a while. With the Maid example they all seem to be using the same body type, which cuts down on the work since you can just use the same mesh and rig to get different poses if you're not sculpting them from the ground up. If you wanted to get a 'head start' I imagine you could make asset packs, X number of body styles (shortstack, muscular, anime etc. all basic popular body types we see on these kickstarters), X number of heads with minor variations (bottom fangs for Orcs/Goblins, top fangs for vampires) etc. and then just dripfeed releases out. The main things that take ages when it comes to 3D modelling is rigging the bodies for posing and doing the supports for 3D printing. If you're purely sculpting them, then the rigging and weight painting (the worst part of process) can be ignored but you're going to have to manually sculpt every body for posing, so it's swings and roundabouts but some people can knock out basic body sculpts in a couple of hours. So you'd probably look at a full months worth of solid work to get everything set up and then could coast for maybe 3-4 months on sexy pinup fantasy/sci-fi ladies since, as Tom says, they normally make a couple of grand.

There once was a barmaid named Gail

Does Tom not know you can click the mouse wheel to open new tabs?