Dont think you are gonna find a cut proof vest. I think the purpose of the vest is to minimize the impact and be resistant...not necessarily cut proof....but giving the dog flexability and movement. If you find something cut proof....it will hinder your dogs movement and probably be extremely hot...both being deadly for your dog.
I have had good luck with uglydog and cazadores.
Exactly on nothing cut proof! I'm all about lightweight and something that can breath and move and the dogs can swim in. That why I like anything that's made out of ballistic nylon. Armadillo is nice cause it's all 1682 ballistic nylon and you can wash it and it breaths really good. Those Duncan vest are made out of seat belts which is ballistic nylon compressed hard together which is a plus too. On the catch dogs I feel you can make them less breath and add more material since there not running miles like my bay dogs. Also I've learned to not tighten my dogs vest to tight and let them be loose a little.
Vince