It looks like Mercury WAS the problem. Andy Cutler's frequent low dose chelation protocol on LivingNetwork describes the reasons why single free thiol sulfur foods cause problems with those with mercury burdens. I never had Amalgams but believe I was exposed as a kid when I dropped a bunch of mercury I was playing with (we had collected it) in the carpet and then tried to vacuum it up. Since that time I have noticed increasing symptoms which now fit with the mercury hypothesis. I'm now 9 months into chelation and beginning to feel much better (after going through some difficult months in the beginning). The sulfur sensitivity may have decreased some but definitely isn't gone yet but I believe it should start clearing up here over the next 6 months. I'll probably have another year or so to go in chelation at this rate.
I'm QUITE clear that the symptoms are related to mercury however. Will try and update this if and when the sensitivity is gone.