A friend of mine has been working on a noise-marine-centric Emperor's Children force. At some point this seeded the idea of a "sound system dread" in my imagination. I don't follow the Chaos product lines much, so after a bit of looking I found out about the Sonic Dreadnought model; but as far as I can tell it is discontinued and not represented in the rules. I converted an old boxnought using a few bits, and lots of greenstuff. Rules wise, it could proxy for a Hellbrute or some other Chaos dread.
I'm going to give it to my friend when we start gaming together again.