It's been suggested to me to use the box wine bladders to store my developer in due to it's convenience and the fact you can squeeze the air out. I have worked in various chemical labs for 20 years and we currently receive some of our liquid mixes in these containers at 20L volumes. I was thinking the 1 gallon cubes might work well for storing 5L of developer in (well, just short of 5L anyway). You can get a normal spigot for them as opposed to the tube clamp and if they are the same as we receive the other mixes in the bladder is a thick, flexible plastic. When not in use just tip the box so the spigot is up and they can't leak. Bonus is we get discounted pricing and free shipping since we have been using them for many years for other supplies.
US Plastic sells very inexpensive 500 ml amber glass. All of my film and paper developers go into these and stays wonderfully fresh. I don't think you can do any better. Every time I've tried plastic for devs i end up getting burned. Plastic is fine for stop-fix.