I was sick of my BeeBots rattling around in one of my bags, and the only 'official' storage I could find held only 6 BeeBots. A quick trip to the local foam shop and I got a few pieces custom cut to fit a spare bag of mine. A little Tetris with a template to make sure they fit in, and then careful cutting with a very sharp knife.
This new setup holds 12 BeeBots, 6 mats, spare batteries, BeeBot rulers, pens etc. Everything I need to do a session in class :)