I think if you're having to worry about makeup air cooling the house down than your fireplace heats it, that's less to do with chimney placement and more with how the fireplace is designed. I.e a gas flame in a fireplace with no appreciable thermal mass and a chimney that pipes the heat straight out is where I'd look to first as a problem.

A massive stone fireplace that's heated with a single load of fuel, then has its chimney flaps closed to keep the heat from escaping, is going to be much more efficient. I wonder if maybe the fireplaces in many parts of the USA are actually designed to not heat the house too much, given the usual weather in e.g. Texas.