I haven't done it yet, but I'm planning on using a ice hockey goalie bag for my lighting kit. These bags are huge. One that I'm looking at is 44" by 21" by 21" for $60. http://www.ebay.com/itm/New-DR-X6-ic...item1c1ee8ca68
By comparison, the Calumet bag is 34" by 15" by 8" for $180.
Of course, the goalie bag doesn't have padded dividers. I'm planning to build some basic ones myself. I think I'll be able fit four light stands, background supports, four Einsteins, PLMs and bits and pieces into the one bag. That is the plan anyway.
There are other bigger goalie bags around, but I'm not sure they have wheels. I haven't done too much looking yet.