I don't think that they make an airweight with a 3" barrel but they did make a run of airweights with a 2.5" barrel. I like the concept but I don't know how easy it would be to find holsters for this length of barrel.

Revolvers - Smith & Wesson

To find the model I am talking about choose 38 caliber handguns and go to the top of page two and you will see a 638 with a 2.5" barrel. SKU #: 162523