heat Bell Pepper Sauce...waiting for heat

You'll never know if it'll work until you try it. 
 
Other than using extracts, I don't know of any HOT sauces made without a chile of some kind.  If I remember your other post, the Thai's will leach some flavor into the oil, so there will be some chile flavor added to the bell sauce as well as the capsaicinoids that will have transferred from the chiles to the oil. 
 
What's the point of not adding regular ol' Thai chiles to the sauce?  It won't take much to give it some heat. 

I'm experimenting with different ideas and flavours. Once I try the extract I am going to use the left over Thai chili's in a sauce.

I made a "pepper less" hot sauce - it was basically a roasted garlic sauce. I ends up putting in like 10 grams of dried Tepin, but that was more to add little speckles of red to a white sauce.

Experiment away! That's 99% of the fun of making it. If you make something gross, you'll learn something. If you make something unique & great, even better!