$510.00 for an Aluminum cover for the ARC Ref. 10?

I was in the LAOCAS in the 90's, and attended all the shows in California. I also accompanied Brooks to CES every January for years, but dropped out of Hi-Fi for awhile, visiting Brooks only occasionally. He became a customer of mine, buying a bunch of Vintage Drums (60's Ludwig and Rogers).

I'm slowing down in my old age, and getting back into it. If you remember seeing a 6' tall guy with a long ponytail who wasn't Ralph Karsten, it was me ;-).

Why not take the old one to a sheet metal worker, and have him/her make you one of sheet aluminum

Steel would be cheaper and better. If it is flat you should be able to have it locally made.