I dehydrated some green tripe in my machine once. ONCE. I don't think I've smelled a more awful thing in my life, but I thought Kaiju was going to simply burst he went so nuts for it. I think some prepared raw companies make little moist pelleted green tripe normally used as topper for kibble, but those would probably work very well for training treats too.
Besides that, pretty much anything dehydrated is his favorite. I did one time rub down a pound of liver with about a half teaspoon of garlic powder and dehydrated that. I accidentally distracted my entire class and had to remove it from the room - none of the other dogs could concentrate and they kept running over and sitting in a circle in front of me!