You gotta do what works for you...
I've seen ultrarunners who just carry handhelds from aid station to aid station, while others run with hydration packs, and I don't know that anyone's taking notes--they're just running their race.
More often, I've seen runners carry handhelds or wear lumbar packs on the 'shorter' trail races. Nathan, GoLite, Amphipod all make some pretty good lumbar packs. But, if bottles and a belt hydration system isn't for you (how much are you drinking in 8 miles?), just stick with what works.
You'll see all sorts of hydration systems out on the trail....