It definitely sounds interesting. One recommendation I would have is to make sure you have things in stock and ready to go before you start accepting orders. Too many companies are accepting pre orders and failing to deliver, or delaying over and over...

Launch it right and you will have many many satisfied customers and word will spread.

I think the idea has potential. I'm not sure I would use it though. I prefer to manage my own wallets and am kind of paranoid with trusting another service to hold them. Also, even if I used such a service, I would still do manual backups just to be safe. So I don't think this would be very useful for me.