Right rear thump

It might not be the same thing, but I tracked down an annoying rear sound to the rubber blocks on either side of the hatch that help keep the hatch aligned when closed. I'm only guessing about the actual mechanism that caused the noise, but I suspect the two rubber surfaces [one from the hatch and one from the body] were getting somewhat stuck together -- or at least held in one position by simple friction -- and then when they did eventually move [when the body flexed enough -- as in when cornering or hitting an entrance ramp at an angle], it made an abrupt sound.

I just took a rag with some 3M lithium lube [like they use on door hinges] and lightly lubed the rubber surfaces that touch. That was the last I heard of that noise.

 

You might also check the exhaust system hangers in the right rear under the car. The exhaust system has been known to make some metallic clunking sounds.