Cougar,
My brother and I made one useing some electrical tubeing and an old training wheel works great. The two wheel ones would probally work much better. I also have a plastic sled type one that I use most of the time because it is easyier to store in my truck. I just leave it rolled up in the back this way I' ll never forget it.
It is also suprisingly easy to drag a deer out of the woods by yourself with it, I would definitly recomend you giving it a try, I' ve had mine for about 7 years now and love it.