I have seen a few, and had one come out of a den about 20 yards from where I was calling. I see dens pretty often and usually find the dens in areas that are flat and fairly soft. The den will be freshly dug with a 8" - 10" hole and a mound of dirt piled up on one side of it. As Bear said, most of the one's I have seen have also been pretty close to agricultural areas, but not right in them. Also usually in areas fairly open, but with a lot of Mesquite.
Personally, if I was on your side of town, I'd be walking the areas just inside some of those mesquite covered washes east of San Tan Valley.