Making a diet with high quality, large proteins and a sweet potato (over simplified) is a good way to reduce or eliminate practical fat from the diet while providing the best proteins for management of renal function.
This article at DrJohnson.com is pretty thorough discussing the how and why of the diet, and it's an easy diet to make for a dog with BOTH pancreatitis and kidney disease.
The pancreas x kidney diet also describes how you could modify and feed this to your regular dogs, the ones that have NO kidney issues, and NO pancreatitis.
Here's the article describing home made diets for dogs with pancreatitis and kidney disease together: