I understand why we are not allowed to delete our own posts. It can make a horrible mess of a thread if some goes on a rampage. But have you considered allowing a user to delete their own post as long as no one has posted after it? This would clean up all those "sorry, double post" entries.
I'm working on settings that will allow users to edit or delete posts within a certain amount of time, but then only allow appending changes to posts after that time period has passed. This should provide enough time for users to catch accidental double posts and delete them.