I built a weird custom Moog synthesizer once, and then a few years later, I rebuilt it.
I took a Moog Slim Phatty (Why Moog? Why?) and an Alesis Q25 controller and hard-wired them together. I had a few questions, and everyone at Moog was super nice and helpful in my quest to destroy one of their products.
I originally built it out of cheap plywood because I needed it quickly for live shows, but also because I wanted to have a basic template to work from before I attempted building it out of a nice hardwood. It remained cheap plywood painted aqua for several years.
While shopping for wood for another project, I came across some really nice dark walnut boards that I couldn't pass up. I inlaid an Ominoptra (a wood-burned pendant made from the falling limbs of the dying tree in my front yard) in the right cheek of the synth, and hand-oiled the walnut outside on the deck instead of watching TV.