How can I get a tumblr url that's taken?

[Yousif]

Bad idea, the URL is the users, even if they are inactive, they still have property over it. Even Tumblr cannot give you the name, unless with the permission from the owner of the URL.

Also, you cannot just go around pretending to be a business or corporation, they will always ask for proof of the corporation's existence, along with the company's name, number, e-mail, etc. and yes they will ask for your identity.

But if the owner of the URL insists on permanently deleting the account and giving up all ownership for it, they can contact tumblr and make it "free" again, meaning that the name will be open for anyone to snatch it.