When you want to withdraw, come over here and show up, I help you send what you have to address(es) you control on your own wallet, minus a small % or storage cost fee.
Anything online (exchanges, online web wallets, even your own bitcoin-qt wallet connected to the internet) is out of the question.
I get what you mean, but I think you contradicted yourself with that second sentence. Anyone who wanted to use such a service like this wouldn't have their own bitcoin wallet ... they'd just be showing up at your doorstep and wanting either cash or wired to a bank account.
I'm staying out of fiat. That's their problem. By the time they come wanting their bitcoins, they probably know a little bit more how to secure it on their own.