Saw a reference to this in the awesome firefall art dump thread (here - http://www.polycount.com/forum/showthread.php?t=115361
I know a lot of people use this method, but realized I had never seen a video focusing only on the technique, so whipped one up real quick to demonstrate. This has really sped up my modeling of hard surface stuff. I still use a lot of control loops, but when speed is really of the essence, this can oftentimes make a big difference in time, without too much difference in end results.
Smooth in 3DS Max - YouTube[/ame]
Malcolm posted a way to do this in Maya, though I have not tested it myself.
File menu> Proxy Subdiv Proxy> Select smoothed mesh> channel box set keep hard edges on> hit 3 on keyboard to smooth again> now move points on the subdiv proxy cage and harden/soften edges as needed.