Specialized is making some pretty serious headway in the 'all-mountain' product category. Supposedly, their '07 flagship bike weighs around 27 pounds and has about 6.5" of travel.
Also noteworthy is Specialized branded front and rear suspension. (they're Fox products) This suspension trend includes previous players Cannondale and Scott, although they don't license an independent suspension manufacturer.
Whether or not 'all-mountain' is a needed product segment–time will tell. It is a compromise at the end of the day, but each year 'all-mountain' bike technology seems to narrow that compromise.
Right now though, strength of frame construction is an issue with 'all-mountain' bikes. That amount of suspension (exceedingly more and more efficient) makes a bike maybe more capable than its lightweight construction allows.
I guess 'intended use' plays a role in protecting the manufacturer from would-be cliff dwellers. But its a point we should take seriously.
Look before you leap. (into the market, etcetera...)