I just created a new plug-in called cerb5blog.auto_close. It automatically closes tickets that haven't been updated in the last so many day's. It will also add an audit log entry when the ticket it closed if the audit log is enabled.
Links to the project page.
http://cerb5blog.com/project/autoclose
Links to 5.2 and 5.3 releases.
http://cerb5blog.com/project/Releases/52x/1.0
http://cerb5blog.com/project/Releases/53x/1.0
Thanks
Robert