Take USB stick. Mold a clay figure or tablet around it. Sunbake it.

A cast or formed metal brass or pewter decorative paper weight would do fine -- unless the authorities became suspicious of the sender or recipient, as acoustic or even more sophisticated inspection might be used. A Dremel tool would suffice to open the base in the appropriate place. If one desired to reuse the object just have a back piece that is soldered around the entire bottom edge. But this is getting to be non trivial.  

"It is not necessary to have hope in order to persevere."