I think of this as a subset of the "I want to move N bitcoins from my wallet to a USB stick that I'll put in my safe deposit box so it cannot be hacked", "bitcoins as a long-term store of value" feature:
https://github.com/bitcoin/bitcoin/issues#issue/2
A solution should:
+ Make accidental double-spending impossible (or at least, very hard)
+ Remove the private keys from your wallet so if the wallet is stolen they coins are safe
+ Be as close to 100% safe as possible, even if your computer gets hit by lightning at exactly the wrong time.
That last one is the tricky bit.