Here's video of a deer being skinned using a winch and cables - it's just a simple prototype version, with the deer laying down on a tarp on the ground, which isn't that great since lots of hair remains stuck to the meat. The clamp is an EZ-Skinner and was purchased online, but I think they no longer make it, which is really sad b/c it's awesome. A machine shop can probably make you one, or with some ingenuity you can make your own.
I've developed a much better version since this video was made, allowing an easy hoist by the neck up to a branch using first a pulley from a gambrel, and then an easy transfer to cables (for strength while pulling the skin off), and then an easy transfer back to the pulley with a gambrel attached to the hind legs for ease of butchering.
I'm hoping to get a deer this season so I can test it out and post an updated video...people can just make their own since it is so easy to put together, or maybe I'd even make and sell the kits to anyone who is interested but doesn't have the time / desire to make it themselves.
The nice things about a set up like this is that you can use it with pretty much any animal bigger than a squirrel and it takes up so little room. The cables loop into a neat little pile no bigger than the clamp, as opposed to the stationary skinners made from pipes / tubes weldded together. So if you don't have a lot of room in your garage / shed or just don't want another contraption taking up space, but you do have a couple of trees or sturdy structures to attach the cables to then this is great.
http://www.youtube.com/watch?v=M_ykGB3ZGfU