Where can I find a download of the vBulletin 3.5 Classic New style by Zachery?

You can download it from here (http://www.vbulletin.com/forum/showthread.php?t=133449).

that's only for 3.0 though :(

Yep. A number of styles have not yet been updated for 3.5.x. If you know your way around the template system you should be able to update it your self.

There is a compare templates option in your admin CP, so you can update your code and still retain the style variations.