I've worked with multiple customers to do camoflagued outdoor deployments. The plastic rock shells are good so long as you don't expect long range coverage. Additionally, not only does the shell attenuate the RF, but it being at ground level reduces RF propagation.
We've also worked with customers to put APs inside lighted pylons in corporate parking lots to serve as hidden security cams with wireless backhaul, etc (all of those were machined and built custom).
As far as the rock abuse, they are not usually meant to be 'abused' (which I assume to mean walked/jumped on, etc). Those usually require specific fomulations of plastic of that they be made of fiberglass to support the extreme weight applied.