May have posted this some years back. In the early 90s I picked up one of "Websters Displays" foam chest forms, these come with a wooden base. The front and back are molded and glued along each side. I cut the two halves apart, removed the neck "stub", ran a 2"x2" between the shoulders and ran a one inch dowel from the 2x2 up the neck opening. This allowed and held a foam head to fit on/inside the neck stub. Drilled holes in the end of the 2x2s and cemented in a bolt with a wing-nut, allowing arm atachment and the arms can be positioned. Arms were made from 2x2', foam-wrapped for padding and wired at the "elboes." Picked up the hands at an after-Halloween sale. The way the chest fits on the base it would be simple to construct "hips" out of a 2x4 with a dowel running up into the chest where the base dowel goes, attach "legs, etc. and make a complete unit. When I've used my two at a show display I only used the upper half resting on the ends of the table(s). Easier to carry (you can strap them in on the back seat with the shoulder harness, makes it look you hve a couple of military guys in the back) and you don't have to put a complete unit behind the table or move a table to make room.
While in Tuscaloosa bought two female mannequins at a store going out of business, performed a double mastetcomy on each with a belt sander. Had one in a Japanese uniform in the foyer and one behind the bar in the den. The foyer one had it's hand out so a T-14 just fit, scarred the crap out of the delivery man when he brought in the last box of paper and turned around and saw a "guy" pointing a pistol at him. Unfortunately, the weight of the pistol finally broke the hand. The one behind the bar, with only the bar light on, got me a time or two when I walked in the house at night.
Now have a little guy, about 5' high with a "Garfield" face dressed in a Japanese uniform holding a rubber 99 Nambu light, rubber 99 rifle slung over his shoulder. Had to paint shoes on him, couldn't find anything to fit.