And how to make them! I figure some here probably has need of this info! I can tell you from terrible experience that this method is much more comfortable for your model than duct tape alone.
1) Acquire a restaurant sized roll of saran-wrap. Restaurant supply stores will have it, it costs about $20. Also pick up a roll or two of duct tape and lots of old newspapers.
2) Find a very patient friend or someone that owes you big time.
3) Wrap them in plastic wrap, many layers thick, until it's no longer transparent. This might take a awhile. Bring snacks for your model and helpers.
4) Use duct tape to reinforce the armpit, crotch, knees, wrists and ankles. Also put a strip of tape where you're going to cut it apart. I put it from the neck down the arm to the wrist, and from ankles up to the armpits.
(should looks something like this!)
5) Cut it off, trying very hard not to cut your model (I got poor betty twice )
6) Re-tape the seams that you just cut, and stuff with newspaper or whatever.
7) if you want feet or hands, you can do them separately and attach them. Heads will have to be made up yourself, don't think you should wrap your friend's head in saran wrap.
8) Yay! Now you have a light, portable version of your friend! In my case, I'm suspending them from the ceiling, so they don't need to be self-supporting, but I'm sure you could figure out how to put an armature in there before you stuff it!
And just for kicks, my senior portrait, which I can't help but laugh at everytime I see it. I thought it was head-and-shoulders only, so I wasn't expecting alpaca in the shot.