I think a not-so-mythical one near-perfect container for many people might be an Ursack, with the idea of renting a canister for the limited number of times that a person backpacks where they're required.

My experience in national parks that require them is that they often have canisters for loan or rental at the same backcountry office where you have to go anyway to get your permit and perhaps work out your specific campsites.