I think the only 2 knives using that bushing system right now are the Manix 2 and Para 2. However, there are some other extremely smooth knives.
The Sage 3 is incredibly smooth. Probably smoother than the Manix 2, or maybe any other Spydie I own. The Sage I (and I assume the Sage 2) is very smooth as well. Pretty much any Spydie liner lock-My Military and Michael Walker are also extremely smooth to open, as is my Caly 3/3.5 and Stretch 2.
I think practically any Spyderco can be made to be very smooth with the right adjustment and possibly some lubrication. But in particular, the Ball lock, liner locks and comp. locks seem to be the smoothest (as well as the new Bolt Lock).