As I read through this thread again, I remembered that before our current use of plastics, there was a time when cooper-made wood barrels were coated inside with pitch, that is natural pine tar, to make them waterproof. Hate to say it, but this too is oxygen permiable, and was used a hell of a long time. I am of the belief that we make beer to drink it, not save it for posterity.

Please note that this is just my opinion, and your milage may vary.

Best regards,
Alan

edit - here's a thought, maybe we should line our modern plastic barrels with pitch?

Wild Brews has a table listing oxygen permeability of various vessels. Oak barrels are certainly permeable, but nowhere near as much (as I recall) as the plastic bucket. Even a glass carboy lets in oxygen, via the stopper material.

A local place like this
http://www.lexingtoncontainercompany.com/

that sells used bulk food containers may be something to look into. If you were anal about oxygen permeability you could submerge them in water or tape them up