We don't have those kind of trees up here in the Mitten, but that's a really cool idea. I guess they could make ours look like giant pine trees, but it'd probably be a lot more involved. Looks a whole lot better than just a plain tower!
I worked at a convention for the National Assocation Of Tower Erectors one year and you'd be surprised at all the ways they can disguise cell towers. Trees are the most inconspicuous but they've also put them in church steeples, billboards, and other non-tower-looking structures.
Yes, due to NIMBYs this is starting to happen more frequently, though it has been going on for years. Seems to happen a lot when store/lot/school/church/whatever decides to lease space to a tower/cell company.
This seems to be a great compromise, as evidenced by the photo in the OP (you'd not likely know it was there if you were driving by).
I saw a cell tower that was disguised as a tree but I can't remember where it was. I know I saw it somewhere during vacation last September. It wasn't a palm tree and it had those transponders on three different levels down the tree. On each level they had fake leaves trying to hide the transponder things. It looked really weird. Not sure if it was in Utah, Nevada or California.