Bumping an old thread but here are some of the network operating now:
En Vivo (Westwood One) - En Vivo is an open format mix of music featuring a variety of genres. Music includes Spanish pop, tropical, regional Mexican, top 40 English and Latin alternative.
Fierro (Westwood One) - Regional Mexican, based at La Grande 107.5 in Dallas.
Juan FM (Westwood One) - Variety Hits similar to Jack FM but with Spanish language music. Hits from ’70s, ’80s, ’90s, and some 2000s.
Ke Padre - Spanish language hits from the 80's, 90's, through today.
There are also a few other networks like Exa FM and La Mejor but I don't think they are a plug and play 24/7 network.