You know what might be good? Fino sherry and dry vermouth syrups- has anyone tried them? Perhaps that will be a project for another day.
Anyway, I made a cocktail using a wintery mulled beer syrup from Nick's Cove Restaurant, Oyster Bar & Cottages on Tomales Bay near San Francisco. Their Manhattan is simply bourbon, oatmeal stout syrup, and Angostura bitters.