Tex (not so much Mex) are people like Ray Wylie Hubbard, Gurf Morlix, Terri Hendrix.
Tex & Mex are the wonderful Sisters Morales.
Since Lila Downs (all Mex, no Tex) was mentioned earlier, I'll put in a thumbs up for her new Live In Paris CD.
She's great in person & I like all of her CDs.