This is a real long shot, but I have seen breath odor as a symptom of pyroluria , but described as a 'fruity' odor. This reference is my favorite for pyroluria because it points to many other references, but I don't see mention of the breath odor here.
http://www.nutritional-healing.com.a...ding=Pyroluria

But, if you google breath odor pyroluria, you should be able to find some references. Pyroluria seems to be associated with gluten and casein sensitivity.... so it might fit there. Not everyone has all the symptoms listed.

Cara