This last week, in the cold Michigan winter, I finally designed a solution and built it. Hopefully the photos, with really bad light under the cover, will post and show the results. With between 5 and 7 inches above the small cabinets in the salon, the boxes give us an amazing amount of additional storage. The first step was patterning with excess matt board and a sharp knife. I chose the dark and very solid Cumaru (think 3x as hard as red oak and the weight of lignum vitae) because I have a pile of it in the garage. Resawn and then planed to just under ⅜", I box jointed the corners because there aren't many square corners and added an ⅛" ply bottom. The dished front top edge may be cut deeper once we start using the boxes/trays but that will be easy. I also bored a 2.5 or 3" hole in the exposed end of each box/tray for easier handling.
The other part of the project was expanding the storage area between the cabinets on both sides in front of the port. I made an extension piece that covers the original oblong slots with ˝" locator dowels countersunk in the back and I reused the original fiddle. Screws with fender washers hold these pieces firmly to the cabinets. The result, I think, came out a little clunky with the cherry still about ⅞" thick but I wanted the strength versus a sleeker look. I also wanted to avoid permanently altering the factory woodwork in case this did not work.
Thanks for the earlier input. It helped me to better form the ideas that have been swirling in my head for a couple of years.