If you happen to have a sausage maker, such as the attachment for the Kitchen Aid mixers, or the stand alone models, perhaps make some home made breakfast sausage links? I've made my own sausage patties in the past with a package of plain ground pork, plus all the recommended seasonings, and was surprised how good it came out. My only gripe was that when I made the patties, the meat came out a bit too dense from me molding them by hand, whereas if you had one of those sausage makers which dispensed the meat into a casing, it would probably avoid this issue.
Or perhaps just simply slow roast some small breakfast hams - I'm assuming someone is probably going to bring an egg dish or a platter of scrambled eggs, and the ham would obviously pair well with it. Many grocers sell shrink wrapped packs of "ham scraps" which are just odds and ends slices from whole roasted hams. You can simply throw them in a deep baking pan with a little water or ham stock and cover with foil and roast them.
Some au-gratin potatoes would also be a nice addition and would hold up well to being heated for a long period of time.
