The vents on a MacBook are along the hinge between the base and the display. Just because they're not ugly, doesn't mean they're not there. Placing your hand below this hinge will give you an idea of how much hot air is being moved by the "passive" cooling.
Just wanted to share that OS X Lion on a Late 2008 MacBook (MacBook5,1) is running V2 (2.7.5) with no issues for me. I haven't tried any of the TPVs. Third-party 32-bit kernel extensions are another matter though.