another option?
ingredients:
- pen/pencil for writing: 1
- paper to write on: as much as rquired
- 16-sided hexadecimal dice: 1
- an even ground to roll the dice 64 times: as big as possible!
congratulations you now own a private key. not to get your bitcoin address you need:
- some tool to convert the hexadecimal result to a bitcoin address.
- a DVD with live linux to run that tool
now you are only trusting ECDSA and hashes to be safe.
Or just sit in an outdoor cafe, and write down license plates numbers of passing cars.