Vimperator Style Extension for Safari 5?
Not really. I've been hoping for a good one, but I keep coming back to Firefox and Pentadactyl, a Vimperator fork.

Safari does have Vimlike and Vim Keybindings, but Vimperator and Pentadactyl are miles ahead in terms of features. If all you're looking for is Vim-style movement and the ability to follow links from the keyboard, those should do the trick, but I miss a lot of the deeper features that Pentadactyl offers: javascript evaluation, quicklinks, ability to yank links from the keyboard, and much, much more.