As you pare down the weight and size of a tripod you're obviously going to be sacrificing stability. But for a lightweight camera, and if you don't try to do one-hour exposures of the Milky Way, a very light tripod would be fine. There is, for instance, the extremely good Gitzo Mountaineer Sport Carbon Fiber tripod. It'll hold close to ten pounds, and extends to a useful height of nearly 5 feet, while weighing a non-unreasonable two pounds, ten ounces. But oh it's cost$500. Not practical, probably.
Better, I suspect, would be the Cullman Model 1002 Compact Tripod ($60). It extends to about three feet, weighs 19 ounces, and costs just $60. Another good choice is Gitzo's Weekend Tripod ($215), which is a good quality, full-size tripod that weighs two pounds. But, you'll need to buy a head for the Gitzo, something like Bogen's 3028 head ($35).
Another option is to buy one of several tabletop tripods, with are very small and surprisingly useful. Bogen makes a little tripod, the Model 3007, which fits into a pocket yet supports three to four pounds ($60) on any suitable surface. I've found that table tripods also work well as supplements to handholding a camera. By placing the tripod legs against your chest, you can greatly stabilize a camera for slow shutter speeds.