School in AZ (a.o.)
Goodday Winch Launch,
The few references I can mention from personal experience.
Naples Air Center in Florida, a combined FAA&JAA school: I did my FAA PP Certificate (selfstanding) with them, happy. Hadn´t noticed many on higher training there at the time, not that I recall that is.
Sheble Aviation in Arizona, at the time in Kingman, they seem to have moved elsewhere within the State. Done CP-SEL-SES-MEL-IR with them, happy. Now they advertise also MES and Glider (re: your name ...).
For anything not "on the basis of" the requirements include theory exams for which you may want to prepare before moving in. Gleims mentioned upthread are good material.
In Sheble´s I do recall people coming in (from within the USA as well as from overseas) to do their ATPs.
My last time around had been in 2007, do let us know your experiences, where ever you may go.
Best of luck.
For Glider another reference: Seminole Lake, Florida ...