If you're doing cold storage and think that somehow involves Bitcoin-Qt you're doing something very wrong.
Use Armory for cold storage.
What's wrong with QT? It has been audited to an extreme. Armory is great with the paper wallets but putting a wallet.dat into cold storage should be ok.
I recommend against just using the wallet,dat file for your cold storage, as the wallet.dat format may change in future client versions, possibly loosing compatability with the current file layout (berkleydb vrsion incompatibilities, or dropping bdb entirely); making it a pain for you to read the keys from it.
Just dump the privkeys (or evern better, theres a dumpwallet command addded to bitcoin client which dumps out the wallets whole keyppool in a nice table for you). and save that for storage, pipe strait into openssl, or gpg, or whatever if wanna store encrypted or just to aviod writing raw key to disk/stdout...