@awerby, I was hesitant to suggest SLA or SLS printing for something that could be eight inches square, due to the inordinate cost.

I like your idea of sending test prints out to model building services, though.

I suspect decorative brass isn't going to have too many fine details that would be lost in acetone smoothing, although acetone smoothing does indeed remove the tiny stuff. I printed a Yeti-clone mug handle with PLA, then put elbow grease into the equation, using micromesh all the way to a mirror finish (on some parts) but that's possible because it was mostly a cylinder. Any surface changes at all would be impossible to sand so smoothly.

I'm hopeful the OP will continue to post his progress and especially any results that are put into place.