Found two Mountainsmith Day Lumbar fanny packs on clearance at REI in Dallas recently. If you like to carry just what you need for a day hike, especially in Texas heat, and not carry a day pack or an internal fram pack . . . then this bag, or the Mountainsmith Tour (half the size) might be something to look into.
It is about the biggest fanny type pack I could find. Holds to Nalgene 32 oz. water bottles, snacks, camere, rain jacket, first aid kit, etc.
I will also use it when I go shore fishing on Lake Grapevine, or at the coast, or around the ponds in the Euless parks near my home.
This pack is made from 100% recycled PET plastic. For more info go here.