Line a 3 1/2- or 4-quart slow cooker with a disposable slow cooker liner; set aside.
In a large skillet cook sausage, sweet pepper, and onion over medium-high heat until meat is brown, using a wooden spoon to break up meat as it cooks. Drain off fat. Spread one-third of the sausage mixture in the prepared cooker; top with one-third of the halved waffles. Repeat layers twice more.
In a medium bowl combine eggs, half-and-half, and snipped sage. Pour egg mixture over layers in cooker. Using the back of a large spoon, press down lightly to moisten the top layer of waffles. If desired, sprinkle with sage leaves.
Cover and cook on low-heat setting about 3 1/2 hours or until a knife inserted in the center of egg mixture comes out clean, giving the crockery liner a half-turn once halfway through cooking, if possible. Remove crockery liner from cooker, if possible, or turn off cooker. Cool for 30 minutes. Serve bread pudding warm with maple syrup.