In don't want to go off topic or so, but for your chocolate sause you can easily steal recipe ideas from these hot chocolate recipe's, mostly the spice blends.
I have a famous (with my friends and family, because it's a rare but delicous treat) hot chocolate recipe made with whey from making clarified butter (or ghee like they call it in India). I make clarified butter for the baking of fish and meat since you can heat the crap out of it and it will not burn like butter does, still it tastes like butter and not like oil or baking margarine.
Make the clarified butter: put a pack of
unsalted butter in a sausepan in a very low oven (it cannot become brown = "beurre noisette", nor burn). Wait till it melts. Skimm the foam of the top and discard. You'll notice that the butter has split in ghee or clarified butter and whey. Pour the clarified butter in a mold an move to the fridge to set. Keep the whey for the next recipe.
Whey hot chocolate
: In the pan with the whey add 1 Naga Morich (or half if you want the family to enjoy it as well). The whey will still contain a little bit of fat so the capsaicin will be firm throughout the entire drink, but not too unbearable. You can really spice this drink up a lot. Add to the whey as much pure cacao powder as you want (this thickens the liquid either to sauce or hot chocolate consistency or you can thicken partly with cocoa powder partly with eggs, you choice). Crush and add the spices you want to add (this I vary a lot, can be a mix from: clove, cardamom, nutmeg, a few grains of salt, sugar, honey, vanilla pod scrapings, cinnamon, zest of some citrus fruit, black peppercorns, anise star, aniseed, fennel seeds, ginger, coriander seed, ... anything you like really).
Maybe some more ideas down here:
http://www.pachakam.com/recipe.asp?id=3919&RecipeName=Spicy Mayan Chocolate Drink ,
http://whatscookingamerica.net/Beverage/HotChocolate.htm ,
http://car.utsa.edu/Legacy/mayarecipes.htm (2nd recipe on this page) ,
http://www.yucatanadventure.com.mx/cookingrecipes.htm (scroll down a bit to their chocolate section)
Just some ideas really... you can take it anywhere you like. Hope you got something to work with now. And let us know how it went