Sure, you could do rilletes in there. Depending on what version I'm making I'll use salt, bay leaf, thyme, mace, cinnamon, sage, marjoram, basil, nutmeg, clove, and pepper, or just salt, pepper, rosemary, thyme, and bay. Either my approach is to simmer pork loin or and bacon (or just shoulder) in water (with the various spices/herbs) for a several hours letting the water reduce, then pureeing the whole thing or cooking spice/herb-marinated belly in pork fat then water. I read recently of an approach to rilletes made from lightly smoked pork butt that looked appealing. Rub a butt with salt and spices and smoke 15 min. Cool, wrap, chill. The next day braise the butt in chicken or veal stock for 8 hours--this would be perfect for a crockpot--then proceed with whatever rilletes wrap-up you prefer.
I don't really ever cook in a crockpot but they are handy for reheating. The butt you just found, for example, is a good candidate. After it's smoked, rested, and pulled, whatever you don't eat can be frozen then reheated at a later date in a crockpot.