I've seen them, and used one on a couple of hides once.
They do work. There was a couple of things I didn't like about it.
First thing was the blade was so small on it that it took forever. Granted I think I was doing Mule deer at the time. If I would have tested it on...say a Coyote it would have been perfect.
The other thing I disliked about it was the fact that it left "knife tracks" on the hide. By knife tracks I mean cut lines left in the hide like someone combed the flesh side of the skin with a very sharp comb. Now... anyone that knows anything about fleshing machines knows that if you sharpen your blade the wrong way you will get knife tracks in the hide and the reason is, by sharpening the blade wrong you leave a burr in the cutting edge. The burr is what makes these tracks. I could not get the knife tracks off my blade if my life depended on it when I was testing this thing.
But for around faces, and smaller hides, yeah they'll do the job if your in no rush or not doing much volume.
