The Ed has occasionally had 'username amnesties', where people have been allowed to change their usernames but other than that, as you've indicated, you can only simply start again.
Since your old account would still be present (even though dormant) you can't re-use the same email address. However most email providers allow you to create aliases or, of course, you can just create a brand new email account with (for example) GMX:
http://www.gmx.co.uk/