THE MENU

Ketchup improv IV
You can add a high quality barbecue sauce to tomato paste or tomato sauce, and make a kind of ketchup. 
You have to be selective. 
I would not use, say, a Mexican salsa chip dipping sauce for this, but you could I suppose. Some thicker Mexican sauces, red or green, would work better. These mexican sauces tend to lack a desirable ingredient for ketchup, a sweetener or a flavoring that fakes being a sweetener.
Proportions would also have to be "to taste".....