LoveCraftsman sez, "How to make a realistic corpse out of a cheap plastic skeleton in one hour."
Having experienced the tedium of creating a corpse with liquid latex and cotton fiber first hand I found this tutorial extremely helpful. It uses a cheap plastic skeleton, plastic dropcloths, and a heat gun to produce a surprisingly realistic final product. The one in the tutorial took about an hour and looks pretty good, particularly when compared to the latex treatments that take days to finish.
(Thanks, TheLovecraftsman!)