I made some awesome bbq sauce a couple weeks ago for a hog roast we had. I didn't use a recipe, here is what I did though:
I seeded a whole bunch of tomatos from my garden, probably 8-10+ pounds or so. Then I chopped up a couple onions and a few peppers from the garden. I ran that through the food processor (blender woould also work) and put that in a pot on the stove. I added about 3/4 bottle of liquid smoke, a half cup or so of vinegar, some salt and ground pepper, and 2-3 pounds of brown sugar. Stirred it all up and let it simmer, stirring occasionally on low heat until it reduced down an inch or so.
At that point, you can taste the sauce (as if you haven't sampled it a bunch already) and balance the ingredience to your taste. You can add tabasco, cumin, cayenne pepper, more sugar, vinegar, etc. Whatever you think will taste good.
Depending on how thick you want the sauce, you can just leave it on a low heat and let it reduce down, or if it is too thick just add some apple cider or water. If you are in a hurry you can mix some corn starch with a little water and add to thicken it.