Do any of the Android-based wallets support cold storage?
Its not exactly what you want, http://mycelium.com/ for Android does it the other way around.

You keep your private keys safe in QR-code format on a paper or a offline device, then you scan it when you want to make a transaction. Mycelium signs the transaction and forgets about the key.

I tried to scan with my Android device offline, but it does not work. To be able to select previous outputs to send in the transaction, you need to be online.

I don't know of any Android app that can take a raw transaction (by QR-code, SD-card, OTG, Bluetooth, NFC or Chirp.io) and sign it offline. 

I hope this feature will be implemented soon.