How about one of
these Andy
, they take a Micro sd card, I have one with a 64GB card I use in my Nexus 7.
Check on compatibility list under the Buy button.
They are small, about 20mm square and have a micro USB connector under a cap, included is an adapter so you can use it in normal USB.
They ship from Hong Kong, I had to pre order mine so had to wait a while so not sure how long it would take.
HTH
