The local gun store has a S&W 520 (4 inch, alloy frame)
You should probably seriously consider the Model 520, although it is no longer in production (first made in 2005).

It's a steel (not alloy) "L" frame .357 Magnum/.38 Special with a 7 shot titanium cylinder. The barrel shroud might be aluminum alloy, but I'm not sure about that. At 37 ounces, it's not too heavy for a trail gun.