I have been waiting three days for the danish oil, so that I could assemble this. Now I can post the results.
About $10 in parts for the speakers, wires, and bluetooth module.
The wood is PureBond Columbia Forest plywood (maybe Red Oak???).
I had done a design earlier in Adobe Illustrator for thicker wood and had been avoid doing it again for thinner wood. So last weekend I spent some time using Cuttle to convert my design.
(thanks @forresto for the isometric visualization)
Once I converted it was easy to resize for the wood.