Here's an idea that somebody should run away with. Fang-Chun Tsai's Collector USB flash drive is a concept kit that takes all of your spare MicroSD memory cards and combines them to create a USB flash drive.
Tsai's Collector drive can combine up to three MicroSD cards together. Three 16GB MicroSD cards would easily give you a 48GB USB flash drive. The reasoning is that if there isn't enough room to store a file to the flash drive, users can simply expand the storage by adding a higher capacity memory card and they'll be good to go.
I've got a ton of MicroSD cards lying around in a tin and this Collector drive would give them all a fresh breath of air. Make it work like a RAID drive and I'll be sold!
Via Yanko Design