I feel John Constantine would be amused by the fictional existence of obvious cut-rate file-offs of himself.

And there are several of them around, because Morrison wasn't the only writer who wanted to use Constantine in a non-Vertigo title and decided to just work around the ban. Phil Foglio's version was named Ambrose Bierce, complete with hints about how he may or may not be the Ambrose Bierce who disappeared under mysterious circumstances in 1913.