I have been using emptied and washed 2- and 4 litre wine cask bladders for at least 16 years for storage of film and print developers (including 2 part developers such as Beutler), as well as fixer concentrate. Xtol lasts at least 12 months (I've used some successfully after 18 months!).
The casks are easy to fill - remove the tap, hold the circular tap opening upright, pour in the dev. replace the tap and carefully squeeze the bladder while holding open (slightly) the tap to remove the last of the air. You can then place the bladder back into its original box (open up the top where the handles are) and reseal same with tape. Then tape a label on the front of the wine box with name of contents and date.
A 2 litre cask can hold about 3 litres, and a 4 litre holds 5 litres - great size for most larger packets of film and paper developers.
Tony from Sydney