Here's the best explanation I've seen:

SwRI Lighter Side

I had this issue with my 2004 Crossfire when it was fairly new, but the sulfur content standards were less restrictive back then. BP and Citgo gasolines, for example, resulted in the smell whereas brands such as Shell and Chevron did not. So, once I stopped using certain fuels I never noticed the odor again. I haven't tried BP recently in my Crossfire, but maybe I will just to see if I get any of the H2S odor.

Anyway, if it's only during heavy acceleration, I would not be too alarmed. First thing to do would be to try a different fuel.