This is the best list to start with http://www.sanantonionaturalparenting.com/Health_Wellness_Resources.html#pediatricians but honestly, you'll probably have more luck with the General practitioners or family practitioners.
I use Dr. Earp at North Hills Family Medicine near Stone Oak. He works with 2 other doctors, but he is the only one that is open to no vax or alternate vax schedules (so I've heard from other moms). I took my son there for well visits and did not want to start any vax until he was a year old, and Dr. Earp was fine with it. I didn't have to sign any waivers either.
Sorry to steal the thread, but I might be moving to San Antonio from Canada. I'll be looking for a vac friendly doc, so this thread helps. I too would like to primarily use a chiro and other alt. ave. So what I'm really wondering is what kind of health insurance works best for that?