I understand that you can get more space, but has anyone presented the plastic tool tray to a aluminium fabricator & said “ can you make this”?
Yes, the version which John has, originated in a similar way. But replicating the plastic tray in aluminium doesn't optimise space. Additional depth is available, but it varies by year of Morgan. My three cars, 2005, 2012, 2016 were all different under the tool tray.
This is why there is no commercially available aluminium tray on the market. It has to be designed and fitted to each individual car.