According to a Google Tech Talk by the creator, a few people have switched from vi to emacs to get org-mode. The obvious implication is that there is nothing comparable for vi. However, the talk was in July of 2008, so maybe someone has created something since then.
I used vi/vim for about fifteen years before playing around with org-mode (and magit and a few other tools). After that, I felt like I'd been missing out on a lot of useful stuff.
That was about a year ago. I'm still fluent in vi (which I use sometimes), but I can get far more done far more quickly in emacs.
And I track it in org-mode. :) (which also has a view of my current google and exchange calendars and automatically saves all edits in a git repo and pushes it off my box for synchronization/backup/history).
Here is a link to the talk: http://orgmode.org/GoogleTech.html