How to leave? (How to delete, or how to remove, own account?)
Using Jamroom
In my opinion the biggest issue would be that you are trawling a user's content to see what you don't want deleted after they have deleted (or requested to delete) their content. If ever you have to explain that it won't be an easy fix however you manage it.
If you want to check the content of every account you would have to restore it and look through their content, just like if you had to look through their content before deleting it. It takes a few seconds to restore an account, visit the profile tab and move it to a private quota.
But if you want to make your users wait until you approve their request to delete their account, hey, maybe that works for you. Change the account delete button to a custom module button which adds the delete to the pending queue - just guessing but I doubt it's that difficult to do. Seems weird but not difficult.