How small do you want? You'll be unlikely to find a smaller "heating" torch than a cutting torch, but I think maybe you're confused as to what a "heating torch" is. When it comes to oxy-acetylene torches, you have cutting torches with multiple flames around an oxygen jet (and which can accept weird things like scarfing tips that are more made to sculpt and gouge metal than actually cut), brazing/welding torches with single point flames (which cannot be put on a cutting torch head), and heating torches better known as rosebuds that have multiple flames. The smallest rosebud I'm familiar with (the Smith Little Torch 13-662) is still about as big a flame as a cutting torch's pre-heat flame (that comes from the 6 holes).
So, as I said above, are you REALLY sure you want a "heating torch", because that's what you've got (if you don't use the lever).
What are you trying to heat that you're getting too hot? Oxy-acetylene will not "cut" steel when you have a neutral flame, but it certainly does melt it. No matter what tip you put on an oxy-acetylene torch, it will be too hot to soft solder for example (even assuming you're using acetylene; you really haven't disclosed much useful information here - hint, hint).
Are you sure you wouldn't be better off with an air-acetylene torch?
I can respond more. This is what I know/ remember about my torch. My father bought a 2 piece torch in 1978. It had the cutting head and also brazing tips. My father was against brazing so the cutting part was left on all of the time. For some reason in the mid 1980's, my father did not like the 2 piece torch and purchased the one piece cutting torch which I still have.
Years later my friend helped me with a brake job and used a Blue-point oxi- acetelene two hose torch to heat my brake line nuts. That torch could not be used for cutting. I am guessing it is like the 2 piece torch that I had that we gave away with the brazing tips installed. If I were to use my cutting torch for those brake line nuts, it would be overkill and probably melt my brake lines.
I have not used my cutting torch since 2010 because of caring for a sick person and the torch getting buried in the garage . My father bought the biggest aceletene tank he could and rented the biggest oxygen tank. In 2010, I got tired of paying rent on the oxygen tank and bought one, but the biggest one they would sell me is smaller than the acetelene I already owned.
Now, I am able to start bigger projects once again and the torch would come in handy. I have a torch for cutting/ heating but also see the value of a smaller flame for heating small stuff like a brake line nut or small bolt which the cutting torch is overkill for.
My question is, do they make a smaller size tip for my cutting torch for small stuff or should I just buy a small oxi-acetelene brazing torch? I have a B- tank torch for plumbing which I have tried to use to heat small stuff, but it was not hot enough. I do have a propane torch which I know is not hot enough and my Snap-On man would not sell me one of those other hand held torches because he felt were not that useful for me. Maybe I need a torch like radiator repair guys used? Sorry it is long....thanks!