I have been using a string pod for years and it is one of the first gadget hints I give my students. They are super easy to make, small light and compact. A 1/4" by 20 ibolt and a hunk of string, chain or cable will do. It can give about 2 extra stops. Total cost is about half a buck if you have the string, nothing if you also have the ibolt.
It is a very old trick which was commonly used for amateur cine-photography decades ago. The easiest and cheapest way to this is if you have a spare quick release plate with a D-handle bolt (many of the Manfrotto and larger Slik tripod quick release plates for example), tie a string of the adjusted length with a loop at the bottom. Put your foot through the loop and apply upward tension.
I would be surprised if you get 2-stops advantage but it could be possible. Better still, if you use the video mode of your camera, it is almost as good as a steady-cam.
The Steadecam is a very neat application of the idea but I would think a little overpriced. For the same sort of money you can get a cheap monopod.