I had a chance to demo a Cannondale F29 2 (aluminum from my LBS). It's a size Large with Lefty front suspension and XT drivetrain.
The reviews might be a little jaded as the tires were wrong for the conditions of a wintry NE but they're still something for someone interested in the bike.
The bikes awesome, even with inadequate tires it still climbed really well and handled muddy sections with little drama. The stock handlebars are about 4 inches too wide but I obviously couldn't cut them down. The Lefty works awesome and for some reason I just liked the view from the seat looking down, it wasn't weird at all. I've done two rides with it and I can say the things climbs like a mountain goat is really stiff. It's a fast bike and the best features are easily the brakes, the Magura's on there are just awesome.
Someone looking for a fast 29er hardtail should really consider this bike.