That fork modification sounds like a good idea, Graham. I'm visualizing the times bent to resemble a rake. Is that what you meant?
The day that we picked up our steers at the packing house I noticed that they carried a good assortment of organ meats available for retail sale. I didn't notice kidneys (and don't remember ever getting a pack of kidneys with my beef) but a phone call could probably let you know if they are ever available. Cow heel? Never heard of that particular cut, but assume it is a bony piece like the oxtail. I love using beef heart for a pot of noodles or stew. It's probably been 50 years since I've had tongue or brains.
Thing to think about when I'm raising my own meat animals, eh?