I just used a very large grain bag, and lined my bottling bucket with it. Then, when I was all mashed in, I put a sleeping bag around it to hold in the temps. It was pretty easy, and didn't require any equipment at all (except for that large bag, which I already had for winemaking).
You may find that the strainer clogs with the grain, or the grain "floats" away over the side. Otherwise, it should work. The idea is to really soak the grain with the hot mash water and to keep the temperature in the 153 degree range.