Hello!
Flagging is a very nice feature!! I would like to have it too!
My plan is to have all messages in one folder, and the flags could do the rest; inbox, outbox, threads (conversation), etc...
My new ideas:
1.) Show/hide quoted text - default setting: hidden (user definable)
2.) Export threads to html - the formatting could be user definable with css
Best Regards,
Bici