They came out several years ago, along with a line of polymer-framed autoloaders selling under the "Patriot" name. Both lines were intended to shore up the Cobra name somewhat from the low point the company's alloy-based blowback pistols had kept it to.
I handled a Shadow revolver shortly after its release at a local gun show. MSRP at that time was around $400 for the stainless once I was holding. It felt pretty much on par with a current Charter Arms product, or maybe one of the lower-quality Charco or Charter 2000 incarnations of the Undercover revolver.
The gun had an aluminum frame with a steel barrel and cylinder, and came in different colored finishes. For that construction, the gun is still pretty heavy, weighing empty right at 2 pounds (twice the weight of an unloaded all-steel Charter Arms Undercover.)
There seems to be a relative shortage of internet user reviews compared to other guns, simply because production appears to have been limited before the line was discontinued.
I was very intrigued at the time in the DAO, hammer-fired, polymer-framed Patriot 45, but never laid eyes on one.