Can we perhaps expect 3d printed wallet backups from some new version of Armory? Might be worth looking at the materials properties of the various 3D printing substrates out there, see whether there's something with compelling durability.
It certainly would be easy to print a sheet of plastic with your paper-backup info either etched in it or extruding. That would be fairly durable, as well. Especially if you did it with the nylon filament which is like 16,000 PSI and stretches over 100% before breaking.
Plastics (and certainly the type you're indicating) sounds good for many a key storage purpose. Perhaps also, you could design it in two hinged pieces, the hinge mechanism all on the inside? With a lock built in the same way, you'd feel more comfortable that it's true purpose wouldn't be apparent if someone you trust was snooping through your stuff. Or at least that no-one could stumble on it and jot the key down.
Plastics have another advantage; they can be buried in a hole in the ground without worrying about degradation (or metal detectors, in the case of using metal as an alternative that is). Metal would surely still be more durable in a fire, whatever the latest printing substrates can achieve. Roll on carbon fibre printers!
