I've been waiting years for something like this. In the meantime, does anyone have any suggestions of third-party desktop applications that sync with gmail?
What is it that you want that a desktop mail client like Outlook or Thunderbird doesn't give you?
They don't preserve the correct labelling. Google rolled their own IMAP implementation to support putting a single email into multiple folders without copying the email. Thunderbird will take a copy of the email if it has more than one label.