We have two SCS subs flanking the rear our theater for our Wisdom theater (plus a 90i in the ceiling). The bass reproduction is quite amazing, reaching down to 16 Hz while maintaining significant output. Our configuration is "in wall" in that they are behind fabric cover for the theater. The application talked about commonly is to hide it behind a soft or underneath the theater seats and such.
http://www.soundstagexperience.com/...red-subwoofer&catid=63:all-articles&Itemid=50
Here is a picture of them during our theater construction:
http://www.soundstagexperience.com/...red-subwoofer&catid=63:all-articles&Itemid=50
Here is a picture of them during our theater construction: