I've added an app template for this:
Hence, WAMP-CRA using custom authenticator is now available in Python and NodeJS
and David (Thruway developer) is working on a variant for PHP (will be there soon).
Of course you could combine and mix-and-match all those variants into an app using different languages for the different pieces also. Which I think is cool - as it demonstrates a core value proposition of WAMP (and Crossbar.io):
You (developers) should be free to choose your weapon (language) for your app or different parts of your app as it fits. No lock in.