Thanks for all the replies.  The more I consider this, it would need to be a service like LastPass, but integrated with the Bitcoin client.  So, essentially, all wallet decyption is done locally on your machine and we never get a copy of your wallet that is unencrypted.

If you have used LastPass you know how this works.  Never trust anyone with your wallet is right.  Personally I would not want to guarantee other people's wallets, because who knows what will happen?  MtGox being hacked has proven what the risk can be.