Scrub personal user info when disabling a user

So it looks like unless we have a way to salt the hash there isn't a reasonable way to store it that won't be vulnerable to a pretty trivial rainbow table attack, and if we salt the hash, there isn't a good way for us to look up a user that wants to re-enable their account. 

I also think it may be a bad idea to allow a user's account to be deactivated, and then allow someone to signup with their old login, especially if we tie the login to a users's URL name. 

To me it makes the most sense to just leave the login in plaintext, and to offer some sort of "Really delete my entire account" option.