I picked up an Amphipod hrydration belt in a thrift store today and was impressed with the quality materials, design, and workmanship. I looked them up on the Web to find they make several lines of hydyration and gel flask carriers, catering to runners and adventure racers. I got a padded belt with some zippered pockets and a 20oz bottle that is carried horizontally and runs about $40 list--- for 99 cents.
What I thought would be interesting for ultra light use is the small add-on pockets they make for runners and swimmers. Some have spring clips to hold them to you belt or waist band and others have belt channels. They range in size from holding keys and some credit cards to larger units that will carry an energy bar, etc.
The items that caugt me eye are a series of bottles and flasks that snap into holders that can go on your waist belt or pack sholder straps. The have bike bottle style nipples on them, but the bottle bodies are flattened and ride closer to your body with less interference to your arm movement. Looks like nice stuff. REI carries a fer of their products.