Well just substitute the pepper of your choice. Some have good flavor and some have good heat. The basic sauce prep could stay the same. I'd rather have taste over heat.
I found some info on chili sauce you may find interesting.
It seems British sailors brought back from Malaysian a spicy fish sauce called Ke-tsiap. It appears they added tomatoes, spices, sugar, vinegar etc. and voila = Ketchup was born around 1800s.
The British already had mushroom ketchup for sandwiches thus this became tomato ketchup. Now if you add more cayenne, onions, & garlic, you had tomato Chilli sauce. It appears we have been spelling it incorrectly for sometime.
The British took both to the US where locate farmers in the south started to bottle their own variations eg green chilli sauce and today's hot sauce with more and more hot chilies in them. To the North, they "bland" it down, removing most of the heat.
Now according to the researcher - the word Ketchup was used in the US by Heinz. Del Monte referred to it as catsup, but, only east of Mississippi. West of it it is all Ketchup except in Iowa where it is known as Tomato Cornchops. Not sure if this is true, sounds far fetched to me. I had always believed ketchup was Canadian pronounciation and catsup was America. You, my American friends, can confirm or deny this theory.
Well being that I live west of the Mississippi, in TX, I can honestly say that I have never called it, nor seen it called catsup. I've always bought "ketchup" by the bottle, so I'm not sure how reliable the info might be.