I have also found that when a certain need becomes apparent- such as yours - there is a certain satisfaction in scouting around at what may be laying around indoors-or in say a pound shop ,tha may with a little bit of imagination and dexterity will do the job for little cost or even for nuffinatall.
That should the need arrise I could utilize. The boxes that photo slides come in, one of those Italian Chocolate- boxes- a small tin box that once contained miniatures of a famous Highland Malt Anything at all similar a bit of urethane or styrene foam and a craft knife- and bingo top of the range storage for nothing
checking out that first amazon result from hssutton - £8 for storage! lol. since the actual box looks to be no wider than 2 SD cards itself, id probably end up losing the storage box also, haha. perhaps i could fit the sds into the storage, and then finally fit THAT into the tic tac box ;) lol. i just wondered if there were any "official" solutions. i guess not!