I have put things that are more aromatic in the water pan in the MES we have at work. Basically we make a potpourri of different things that give off a strong smells ( citrus peel, cinnamon, vanilla, lavender,......etc.). You have to be careful of the rubs you use if you want to pick up the flavors. Things like chicken, turkey, fish, shrimp and other types of mild meats, vegetables and cheeses pick it up slightly.
One of my favorites was a turkey breast smoked with oak. We put lavender and white wine in the water pan, the last hour we coated it with a current jam. Chilled it and sliced it for sandwiches.