According to a blog
http://rutajacobeadeloscalatravos.blogspot.mx/, this was originally the idea (in 2010) of a señor from Argamasilla de Calatrava, who tried cycling to Compostela using the old king drover's roads (cañadas reales). The idea evolved, has a webpage, maps and some support from civil and ecclesiastical local authorities. It crosses other Caminos with more tradition (as Levante) and joins the Frances before Santo Domingo de la Calzada.
(I remember a panel in a stage, where the Camino crosses a Cañada Real, but I don't remember where).
Pros: it goes by dirt roads; this looks good. Obviously, no crowds at all. According to the promoters, it has interesting ecological traits (especially birds). Some signposting (a specific logo was created). It also advocates the preservation of the old royal drover’s road, always menaced by development. Very interesting point: San Millan de la Cogolla.
Cons: It has some stages with around 4o km (too much for average walkers, acceptable for cyclists) some in flat terrain, others in hilly country; and a very tough one, Vinuesa to Venta de Goyo, 45 km and goes (as far as I can see in their graphic) from 900 to 1900 m (this is around the same height profile of the way from Saint Jean up to Virgen de Biakorri).
http://rutajacobeadeloscalatravos.es/sample-page/
The webpage does not include info about lodgment, which is really needed if they want their project to prosper.
Opinion: for now, to be watched, and see how it evolves.