Belgian Stouts are a pretty rare breed. I have a batch I'm aging right now in an attempt to make a beer approaching Jolly Pumpkin Madrugada Obscura.
Here's the link to The Brewing Network recipe from CYBI: http://www.homebrewtalk.com/f12/can-...bscura-177964/
The sour/wild flavor isn't what you were mentioning, but the recipe might be a little closer to what you might consider. I do like the discussion of the recipe formulation during the actual interview when the "kitchen sink" type approach is discussed for this beer. It's definitely worth a listen.
Also, you might want to consider starting your recipe with light malt extract and then getting your color and flavor from dark steeping grains. This will give you some more control of the product than beginning with a dark extract.