Thom, I assume you know how to make mac-n-cheese, so here is a pic and recipe, Blog link is also provided.
Jalapeno Cheese Sauce:
1/2 cup butter
1/2 cup flour
1 teaspoon salt
1/2 teaspoon pepper
1 teaspoon dry mustard
3/4 tablespoon chile powder, Plowboy's Bovine Bold (more on this later)
2-1/2 cups Half & Half or whole milk.
1/2 cup sherry
2 cups cheddar cheese
1/2 cup each gruyere and smoked gouda
1/2 cup finely chopped onion
1 finely chopped jalapeno
The one change I am planning on testing is to use some Mexican soft cheese, that stuff that is sort of like ricotta, to make the sauce creamier for baking. I also would probably go with three jalapenos for myself.
Here is one that I saw this Memorial Day on the Food Network show "Grill it with Bobby Flay". Not sure if it fits the bill, but I thought I'd share it, for what it's worth: