My friend has been carrying around this empty shell of a Micro Muzak Model 1008 for years with the intention of converting it in to something… someday. Apparently this was used in a university to pump the college station through all the buildings and had long since been left to fall in to ruins.
Using parts you can easily get and very little modifications to the actual case it came out looking preatty good. We reused the original knobs where they were still available for that original look. The tubes were left on the case to look cool, they do nothing.
I admit this is less of an instructable and more of a hey-check-this-out-able, but maybe it will inspire you to make something neat.