Haha! I now have this mental image in my brain of a Here's Johnny! Style cat, sat in the bathtub looking crazy with a dead creature in it's paws, LOL!
My cats have always loved whole tiddlers (young fish, can get them from bait shops sometimes, been a while since I bought any) and they also had these little fishy flavoured disks, and I can't remember for the life of me what they were called. They were grey and had vitamins and stuff in them. My household was also terrible for hiding tiny slithers of cheese in a pile of toys or whatever and making them find them! (i know, cheese is so bad!) Cats went mad for it though.
I also thought about grinding beef heart and making chews and cubes, baked in the oven. I used to make these for the dog but would often bind them with a dab of egg and wholewheat flour. Might have to tinker with a similar recipie for the cats without so much of the flour. Trouble is, without it, it doesn't bind so well. I expect you could make your own jerky from beefheart and chicken strips though.
I have a contact with a farm too, seeing as cats can't have normal cows milk, mine will get the odd treat of a tiny dish of fresh Goats milk when I can get hold of a bottle! or i buy my own goat...
Soph.