Canned goat might actually taste pretty good. :) You might have something there. Kidding aside, why not ask Google to add temp accounts associated to a main account? I would love to have temp emails/identities that I can create and reply to from only one account. Like Visa or MasterCard have temp credit card numbers. Then when I'm done, just toss them out. Maybe you could associate an email/identity to a circle. I think it's early but I don't see many roadblocks.