For a hand applied coating look into Zoops-Seal or a similar product aimed at protecting the finish of billet aluminum.
As you've found, having them re-brite anodized is the only true maintenance-free solution.
You might investigate clear powdercoating, but I'd do a test piece before committing to it, as it may not be the look you want.
As far as automotive paint type clear finish, it doesn't adhere well to a polished surface (no "bite" for it), and often either yellows with time or just muddles the look even if it stays clear.
You'll find that once it is sanded through the original anodizing and fully polished in clean aluminum that it is rather easy to maintain as is if you are fairly diligent.
Just like keeping a fully polished aluminum wheel shiny, you need to always dry the pieces after washing to prevent water spots, and hand polishing and sealing with a good aluminum polish/sealer like the Wenol polish and sealing lacquer paste works rather well, and there are several other billet wheel polishes that are also good if you search into them.
It's the lowest cost alternative by far.