I have a closely related question: I use multiple devices, so I need to have an IMAP server that really is an IMAP server, instead of something the just serves up messages to be downloaded. I have multiple folders, and I read messages from different clients.
I haven't been able to figure out an org-mode compatible mail reader that doesn't seem to want me to pull down all the messages to a local server. [I'm ok if it doesn't read nntp.] Thunderbird, which I have been using, doesn't support links to messages. OTOH, it has the best IMAP client I have found, so I keep coming back to it. Gnus: I regret to say that despite having tried it at least three times, I have never managed to wrap my head around the gnus doctrine that mail is just news, so I cannot use it. VM: I used to use VM, but at least when I was using it, it demanded local storage, and did not include a full-fledged IMAP client. any other suggestions? Maybe this could go onto worg....