Yes there has been many many people with the problem through the years on the ENT forum, and I added some of their experiences in Chapter 16, Revolting Sinus Odor
http://www.medhelp.org/user_journals/show/2322/The-Sinus-Flush
Yes, a lot of sufferers have to been to numerous excellent doctors with no results, so you aren't unusual in that respect. I theorize that the intractable ones who haven't responded to the kind of treatment that Padertha Anitha lists above may have a fungal infection, as many times the odor follows a course of antibiotics, and that hope lies in getting anti-fungal medicine administered with a nebulizer. I don't know that anyone is doing that yet, but maybe you can convince a doctor to give it a try.