I always make my own sourdough waffle batter and go sweet for some things and not for others. For example, when i make actual "waffle dogs" i add some ground mustard to the batter rather than suger.... yummy!
I've made little nuttella logs (sort of make the beginning of a string about an 3/4 inch think on some waxed paper and then wrap the waxed paper all the way around and roll to even out the "log") and put them in the freezer before popping them inside unsweetened waffle batter. If you don't freeze it first it is impossible to handle and even frozen you have to work fast because they start thawing right away.
I've tried twix candy bars and pieces of kitkats but prefer the nuttella logs, even if they are a little fussy to work with.
The kids really like if I put chocolate chips and some crumbled up bacon in the inside. Not very traditional but always a hit.
Mix up some cream cheese, scallions, and smoked trout and spoon that in to the center - you get something sort of like a crab rangoon (except it's trout not crab... )
Cream cheese and jam makes a sort of desserty filling.
Sausage in the center makes a great breakfast (one of the best, IMO).
Ruth (teardrop) & Witt (truck) in the northeast kingdom of Vermont, May 2011