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

This assumes that no packages are X-rayed. But a hollow metal object with an opening that looks like a mold mark might work. Insert data stick, fill remainder of cavity with a metal filled clay, solder the opening shut, grind and polish that surface and glue felt over it as a base. Just don't use a falcon.

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."