This was a common pastime back in the days of Poser 3, before conforming was invented. There was a tutorial on the subject, but it's no longer around. The principle is still sound, though. Start with the OBJ(s) for the clothes, then use just enough of the figure's body parts that there aren't any gaps. As long as you keep body parts intact, morphs can still work. Combine into one big OBJ mesh; edit a copy of the figure CR2 to point to it, and off you go. I made a Vicki 2 character this way - she was almost completely covered by a catsuit, so this method resulted in a much more efficient figure that could be used many times over.