Ahh, thanks for clarifying. After I posted this I came across a sound brick on Bricklink which is the same dimensions as the light brick (obviously). It supposedly makes "space noises" whatever that means...LOL! I ordered it and look forward to finishing the AT-AT with space sounds! :-)
BTW - do you have plans for the base that I saw pictured above? I'd love to build that too. Also, I would be in for an order of the round printed tiles. Thanks so much!!