famous SA6 'phones -- dubbed the SA7 -- have the same adjustable bass / treble ports and removable cords of their predecessor, but in a case machined from solid aluminum with a carbon fiber shell and titanium screws. Inside, the drivers are cushioned by shock-absorbing silicone that lets them take a 14,000 G beating, which Wikipedia tells us is roughly the same rating as a navigation chip inside an artillery round. The company told Popular Science the SA7's thin aluminum shell lets listeners hear a whole extra octave; if that tempts you, you'll only have to cough up $400 and change (plus an extra $100 for a wireless Kleer kit) for the privilege.
Update: Sleek Audio pinged us to say that the SA6 is still hanging around; the SA7 is simply the new flagship. It'll be shipping at some point in 2010 -- we'll keep you posted.