Kept me up all night....
I've plied several old references in my library including Hartink's, Bannerman's and Stoeger, gleaning a little more info with every page. Finally in A.B. Zhuk's work "Illustrated Handguns" I located a wood cut of the Spanish ALPHA as built by the Basque Arms Making Collective; ARMERO ESPECIALISTAS REUNIDAS, in Eibar, Spain by the Orbea Brothers. The appearance is not identical, but very, very similar.
Given the lack of inhibition the Basques seemed to have about bold faced counterfeiting of the Smith & Wesson pattern guns, often right down to the pirating of the S&W logo, this seems more and most likely in my mind.
Lastly, the chambering is also telling. The OP says that a .41 Long Colt will drop into the chamber. According to F.C. Barnes, Case Diameter of which round is: .405". Bore is .401".
According to Zhuk, the ALPHA was also chambered in the 10.4mm rimmed round and sold to Spanish allies before and during the First World War.
Again, Barnes tells us; that the 10.35mm (10.4mm) Case Diameter is: .444-.451", bore is.422". I speculate that a .41 Colt round would drop into a cylinder chambered for the 10.35mm round.
My best guess at this point is that this is a Spanish Copy, loosely patterned after the S&W 1899, and including clear cut S&W copyright infringements. I suspect it was built in Eibar, Spain by the Orbea Brothers as the ALPHA ARMERO and chambered in the 10.35 rimmed revolver round. Maybe by one of my great cousins....
I'm open to learning more and the contributing research of others....
Drew