Ok, you want to create a website that will basically do these things, but will keep the private key on its database, giving it to the person when they arrive to grab it?
Yeah, that may work. I think it is a solid value proposition, but there's the problem of people trusting you to hold their lumens (the lumens they're trying to send). Well, that problem exists everywhere. There's the risk of you deciding to close the site while lumen transfers are still pending and all that.
The encoded private key (or, well, it could just be the raw output of encrypting the private key with the password) would then be printed or turned into a card and the person could give it to anyone else, along with the password.
Despite having a link to your site the card could also have instructions for manual deciphering of the keys.
(I'm just rumbling here, you don't have to take me serious.)