It is still in development, but I just installed the 0.9.2 Beta version of Diary. It is a greatly modified version of the Journal plugin. The biggest difference is that participants get a new blank page for any new calendar day when they click the button to start an entry. Cannot go back and add a skipped day. Cannot go back and edit an old entry. But, on the same day, any edit will open the page for the day.
The teacher has a few options as to which entry to look at and grade. Currently, a participant gets to see all of the entries with the latest entry at the top, and their oldest at the bottom. There are plans to give the participants tools to change the view order and number of entries...later.