In the same way that they make tomato tortillas, is it possible to create french fries with a homemade recipe that is made from potatoes and tomatoes both? My idea is to create something that does not require catsup. 
After cooking 90% of the way, pat fries dry on paper towels and lightly brush with a mix of ingredients--tomato paste, honey, vinegar, garlic/onion powder, and salt. Finish in the oven on very high heat (450-500) until the outsides begin to brown.    If you can only use tomatoes and not paste, reduce the above ingredients in a saucepan, substituting fresh tomatoes for tomato paste.  Reduce to about 1/3 volume, so that it's closer to a sauce/glaze, and use that as a coating instead. 