I've noticed this more recently, when pulling away quite sharply in 1st or 2nd I can hear a clunking noise, I think LapDancer is suffering something similar, I suggested it might be the hub nuts which aren't torqued enough by factory spec but I'm wondering if it's actually my rear callipers.

Are there any other things it might be that I haven't considered?

 

I was having this and re torqued my hub nuts last Thursday and now no more noise. There is a article on the home page of this site that's shows you how to do it.

 

Check rear drop links too.