Meangreen, the rattle didn't go away after I took off the cover. Same noise.
I did like you said, and I listened (using a wooden stick instead of a hose; I pressed one end of a dowel against various places on the motor, and pressed the other end against my ear), and I couldn't find the source of the noise.
Car has 27k miles, and the belt and everything else looks fine.
I don't think it's the converter, because the converter appears to be located in front of the motor, and the rattle seems to be coming from the upper passenger side of the motor. I'm stumped.
Aaaaarrrrgh!
