Sculpted prims are a major advance in economically making objects of a wide variety of shapes, especially organic shapes not readily built from the simple geometric shapes of the original prims. At the moment, at least, one has to create them outside SL, using any of several 3D modeling programs and converting the result to the pseudo-texture that represents a sculpted prim's shape.
The converters that have been written so far, at least the last time I looked, count on one's starting with a sphere--sort of like a globe, at least if there were only 2n-1 degrees of latitude and 2n degrees of longitude (or is that the other way around?); maybe a disco mirror ball would be a better image--and performing only operations leaving that invariant; you can shove the points where the lines cross around, but not delete or add points.
Surely to users of 3D modeling programs, that's like having one hand tied behind one's back. Tutorials and texts for those programs aren't written from the point of view of creating sculpted prims, and don't limit themselves to those operations that leave the conversion to a sculpted prim trivial. To make it easier to create sculpted prims, the converter has to be smarter, taking a shape made by whatever means and finding the sculpted prim pseudo-texture that comes closest to matching it. That may not always be possible, but I bet it is often enough to be worth trying.
"So write one" is the correct response. I haven't. Not yet, anyway. It ought to be doable; something like adaptive integration, but in 3D, and having to limit the number of subdivisions to match the limits on the sculpted prim pseudo texture dimensions.
Comments, especially of the form "Duh, look at [insert URL here]; someone's already done it!", greatly appreciated.
UPDATE: I delightedly announce that I didn't know what I was talking about!
Check out Sculpted Prims: Resident-made Tools in the SL Wiki, and note in particular what at the time of this writing is the last five or six entries: in-world sculpted prim creation tools. So much for sculpted prims being the exclusive province of an elite, or of being "unfair."