Harold,
The standard by which these things are measured is the lightweight S&W j-frame 2" .38. Because the real strong suit of these guns is their easy ability to be carried in the pocket, the covered hammer versions play to the strengths of the design, IMHO--by being snagproof. The current production models of 'Airweight' hammerless, or 'Centennial', snubs are the 442 and 642, which have aluminum frames with cylinders of, respectively, carbon and stainless steel (I'd go stainless for ease of care in a frequent CCW). These weigh in at 15 ounces, I believe.
One step lighter, you can get the 342. Same design, also .38 (and like the above, takes +P), but with a Scandium-aluminum alloy frame, stainless steel barrel liner, and a titanium cylinder, tipping the scales at a whopping 10.8 ounces. Incredibly light. Also about six bills.
If you're gonna go that far, though, you might want to think about having the ability to shoot .357 (what? out of such a light gun, you say? Insane? Indubitably). In that case, you get the 340. 12 ounces, unmatched power to weight ratio, easiest carrying thing around.
These Scandium-titanium guns are, frankly, punishing to shoot (esp. .357s. Ouch.). But, they are made to be carried a lot more than they're shot. They're good quality guns, in my experience. But, people who have the 442 or 642 seem uniformly happy with them, too.
Taurus is the main competitor for lightweight revos, and unless I was under a squeeze, I would just follow conventional wisdom and bank on the quality of the Smith.
Whatever snub you decide on, you're right to suspect you need one. A canonical American firearm.
cg