FWIW: I built a prototype out-board motor enclosure out of birch ply for my upcoming knock-off of a VPI DIY tt. After 2 years of testing I had my local machine shop make the top plate out of 6061 aluminum with pretty intricate details. They even had to make their own custom bit in order to make the finished radius on the top of the plate edge. BTW, they let me supply my own material which was a savings.
When I went to pick it up, I almost went to tears because, in my mind, it was absolutely beautiful. It was perfect!