longaccess.com (Score 1)

There is a startup called Long Access http://www.longaccess.com/ that offers a long-term cloud storage using encrypted data and personal certificates for the encryption. The data stored is AES256 encrypted, and the certificates/keys needed for the decryption are in the user's posession. They recommend the safekeeping of a printout of the certificate that would likely be possible to read in 30 years time.

Take a look at their FAQ for more details.

Disclaimer: I am not affiliated with them, I used to work with one of the founders in the past.