I just want to reiterate my position on this -- I have outlined in the past why I don't want to support directly-encrypted backups. Not everyone agrees with the reasoning, but I'm sticking to it because the ability to recover your wallet is higher priority than having the extra physical security.
+1
Instead, this is being addressed with the fragmented backups. It is a perfect mix of redundancy and security, and can be used very similarly to an encrypted backup without the same risks. Fragmented backups have already been merged into my development branch, and will be part of the next release along with the the RAM reduction.
Can you elaborate what you mean by fragmented backups?
Do you mean Shamir's secret sharing scheme, encryption with a computer generated passphrase, or something else entirely?
For the Mycelium wallet I am leaning towards private key export using BIP38 with a computer generated passphrase which is only displayed on screen (and written on paper by hand). The encrypted backup turned into a JPG image containing the encrypted bits are base58 encoded as text and a QR-code. The JPG is shared by whatever means your phone supports. If you combine this with import verification I'd say you are pretty well off.