Drying the bladders themselves is pretty easy. I typically wash, pour out what they can, then open them up and run a clean dish towel inside. I have one of the Camelbak hanging adapters, but it's really expensive for what it is (though it comes with a set of brushes, if you need one for the tube, etc.). The paper towel wicking trick absolutely works for water removal, though.
My problem is the tubes. It can take a week to dry one of them out, even hanging with the valve bodies removed. I've only seen a good solution for that once, and that was someone's personal project where they had a PC case fan re-purposed to give it some air flow. I tried, but could not find the link. If you could get a tiny bit of airflow down those tubes, even with an aquarium pump, it would make a world of difference.
I was drying a set of 5 for my whole family last time I went through all that, but I usually just put my own bladder into a labeled gallon freezer zip lock with the associated drink tube and storing it there.