one-time

Okay, for an upcoming site, i need a special feature:

A ('n anonymous) user can submit his e-mail-address. By the next cron, an email is sent to the emailaddy with a code(like a hash or something) or an url. With this he can create just ONE node and edit it later, if he wants.

I haven't found such a module yet and therefore i'm planning to write this.
What i'm asking for: Did i miss such a module? What do you think about this idea? Somebody whant to join?

best regards,
dunkelfuerst