New Membership test plugin needs to be developed

It would be fantastic to have a plugin that generated test account email addresses. It would be as simple as testemail1, testemail2, etc. This would enable us to test all levels of membership on sites we are designing. I have already used up my two real emails and find myself at a major roadblock now. Even when I delete an account and try to create a new one, I get a message that says that the email address is already taken.

These test emails could all land in one test account that shows up in a separate browser window.

Complimentary to this would be a payment gateway sandbox plugin.

In the meantime, how can I get around this now so I can test how well my site funtions?