Lowepro just updated their Flipside Series wiTh a version 2. The 200 Is small and will hold a minimal setup and is affordable at $99.99. The 300 will hold a bigger setup and is $119.
Looks better than the original, isn't as big as the Mindshift Backlight 26L and is certainly smaller. The 200 is 11L and has two "rows" and the 300 is 16.5L and has 3 rows for gear.
this should compete squarely with the Mindshift backlight series, lowepro invented the rear access bags, still occasionally use the sport 15L, great bag.