There are hundreds of chess variants in the world, including many which are mundane (even frivilous) but also including some which are great game concepts!

However, the notion of 'combining' two separate concepts together (such as "dark janus chess") has as shown from time to time by enthusiasts not been quite as practical as the theories suggest.

Also, offerings and other things can quickly get complicated and the real meaning of basic ideas lost from a perpetual spiral of combinations.