Where in my area could I find a nursery selling Japanese Zelkova ?

Why do you want a Zelkova? I don't think it would do well as a landscape tree
in Texas. You can undoubtedly get one from Dallas Bonsai Gardens.
Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)