Watch for future collectables. Any unique key that has been specially cast is pretty much by definition a “limited supply” item. I recently spent some time looking into having a custom key cast for the Chicago Drum Show and quickly learned that such a project involves an investment of at least a couple thousand dollars. (I looked to the CAD-assisted machined and powder-coated aluminum keys as well and came to the conclusion that it just doesn’t make sense to produce a custom key unless you can afford to invest a couple grand.)
If you find a custom key from an independent custom drum company, stash it away as an investment! Even though the custom keys from the “larger” companies such as Craviotto are now produced by the tens of thousands, I predict that one day they will be worth some serious bucks! And you know what they say: it’s never too early to start planning for retirement.