I'm one of the people who believes that the oxygen permeability "issue" is purely a myth of glass manufacturers that has got stuck into our collective crow, and it gets brought up whenever someone wants to ferment in something non-standard...
I think it's hooey...no one can cite data from anything OTHER that a glass manufacturer comparing their product to plastic...yet so many love to quote the old oxygen permeability chestnut...
Guess what, the same argument was used when better bottle hit the market by old timers...
A couple things to think about...if there's co2 pushing out, then AIN'T NO O2 GETTING IN.
Also, If you are fermenting and drinking your beer within a couple of months, EVEN IF IT WAS AN ISSUE, you'd be done drinking the batch long before any Oxygentation issues occur...
If you are doing long term secondary use glass...But if you are making a high turnover beer then USE WHAT WORKS FOR YOU!!!
I have a bunch of 3 gallon water bottles that I use for my small batches, AND I'VE NEVER HAD AN OXYDIZED BATCH!!!!
There's been some discussion lately about mounting airlocks on Petsmart Vittle Vaults from the pet store...they're foodsafe, relatively cheap and come in all manner of sizes.
I have read and seen people fermenting beer and wine in some pretty interesting containers...
SO find what works, And test it out for yourself. You're making a small batch, so you won't be out a heck of a lot if you fail...