Given that there is a concept of a vm-imap-default-account, I think it might be helpful if such a default could be used to shorten references to imap folders on the default account, especially since most people are probably just using the default account the majority if not all of the time.
So for example, when doing a vm-visit-imap-folder, why not allow :<folder-name> to be shorthand for <vm-imap-default-account>:<folder-name>? Clearly, avoiding having to type the vm-imap-default-account each time would be a real savings. The result would be to simplify rather than complicate referencing such folders for most people, most of the time. The functionality could trivially be added by inserting the following simple code snippet just after the folder name is read in: (if (char-equal (string-to-char folder) ?:) (setq folder (concat vm-imap-default-account folder))) Fast, short, and simple... (Note I believe this should be faster than a regexp type of match)