I do something similar to the garment bag thing. It was Les McClean who wrote about it somewhere. You basically have a wooden base about 30cm square and a similarly sized frame at the top which has hanging points for the films. Then you basically just have a long material "bag" which seals at the front with velcro. Works great and takes up hardly any sapecw hen packed away.
That is actually the system the Jobo Mistral uses, though added by a heated Ventilator at the top.