There have been occasional posts on a sturdier case for the Mini, and after much searching and pestering of store salespeople and manufacturer customer-service reps, I settled on Saga's TL-60 polyfoam case for those times I want to fly with it.* It is a bit longer (4") than the Taylor hard bag and a couple inches wider across the upper-bout segment, but not nearly as big as some classical-size foam cases I looked at. The internal dimensions are just a skootch larger than the Mini (primarily the body length), but the case is otherwise a good fit, with foam pads that clamp the neck at body and headstock ends. Best of all, it seems very rigid and strong, which is a primary concern for me. It will probably not resist being run over by a baggage wagon, but it seems quite able to resist the normal stresses of stacking, and the foam construction offers better shock absorption than a molded hardshell case in the case of a fall (or toss).
Its general construction is close to that of the old Protec trapezoidal cases or the discontinued SuperCase, though I'm not sure whether the sidewalls have the wood reinforcement that makes those cases so rugged. I have flown a lot with a SuperCase protecting my big swing guitars, and I have a lot of confidence in its design/construction formula. The TL-60 is pretty close. In a couple weeks I will be able to report on a field test, including the current state of airline treatment of passengers boarding with guitar cases. (In the past I've flown with a Baby in its hard case about half the time and never had any problems at all.)
*I queried a trustworthy dealer about the TKL aftermarket foam case, but he thought it was not as crush-resistant as I would have liked. But I haven't seen one in person, so that might remain an option.
