How about....
An application for P2P storage of all wallet files, such that you set yours for upload, and it is automatically downloaded by all other P2P users. Of course, wallet files would be truecrypted.
Unless a way is found to break truecrypt encryption, then the wallets are very safe from accidental destruction, and very secure from those that would do harm with backups.
I like this idea!
Only part that makes me nervous is "Unless a way is found to break truecrypt encryption...". If a way is found, POOF!! All coins are lost. Or, maybe if the wallet is broken into many chunks and the p2p network had no knowledge of which chunks go together but the client would be able to figure that out based on passwords/key files/etc and some algorythm, and then retrieve the needed chunks from the network in order to rebuild the wallet? Or something along these lines. Interesting!!