If you are comfy with PHP you can build upon Lukasz' custom edit handler http://serwatka.net/index.php/en/blog/ez_publish_3_8_new_custom_edit_handler. It is not perfect yet (e.g afaik it creates a new folder everytime the user is edited), but it is very easy to implement and can be nicely done as an extension without using triggers and workflows.
You can also try http://ez.no/community/contribs/workflow/personal_folder but it seems to have some issues on eZ 3.8 and involves changing a core file, so this might not be the best idea.
