That would depend on the size of head, hands and feet you'd made (and whether you made only a face rather than a head), and also on just what you wanted the body to be made from.
There are actually lots of ways a body *could* be made for polymer clay heads/etc. But one of the more common ones, especially for "dollmakers" but not necessarily only them, is to use a stuffed cloth body.
If you're interested in that type, there's info and links on this page of my polymer clay encyclopedia website:
http://glassattic.com/polymer/sculpting_body_and_tools.htm
(... click on the word FABRIC in the list, under "Types of Figures"...)
There are other types and sizes of bodies elsewhere on that page as well... and you might be interested also in a few other pages at my site too (click on these page names from inside the alphabetical navigation bar on the left side when you get there):
...Sculpting-General (> "Websites" especially)
...Heads
HTH,
Diane B.