Some of the reasons for hiding those eyesores involve avoiding city ordinances and actually convincing somebody to let them put them up on their land. They tried to put one of those cell phone towers at the entrance to our neighborhood in GA as a scrub pine.
They offered us something like $10,000 for it over a period of time (4 years?). However, they would get to keep the thing up for 20, and it really wouldn't have looked all that great. I think we would actually have been responsible for the upkeep of the grounds as well.
The proposal was eventually declined. We probably could have gotten 2-3 times as much for the thing, but our homeowner's association didn't need the money. Other subdivisions (it seems that they like dealing with subdivisions) seemed to imply that they got good deals, but there were pretty severe penalties in the contracts for revealing such info.
I don't think they've found anyone else out there to put up their tower for them. Its been about 6 years now and we still have poor coverage in the area.
-Biscuits