So, getting a shot from a couple hundred feet up is pretty difficult, especially using tactics that require rigging from the ground. Any shot wide enough to be worth that kind of height would probably reveal the structure used to achieve the height. Using a cable-rig can accomplish some great effects (I've got several shoots in my file cabinet of ideas that include some weird cable/rope tricks), however the final say on how high you can shoot is dependent on how high the trees, or whatever other scaffolding object you use, to rig from are. If I were you I would run around to the local airports and find out if anyone bases a helo from them. Find them and talk to them, let them know you're a student shooting films and explain to them the idea you have. They'll help you figure out what the legalities of flying in that area are, and if you pitch it right could even be willing to help you out for minimal pay. (I know some guys who'd love to help students out for some screen credit and a couple few good meals or other such minimal fees...)
Talk to them first before busting your butt trying to come up with a replacement technique that will sacrifice your shot. Until you do the legwork you'll never know if you're going to strike gold or not, and if you're really lucky you'll meet someone you can work with in the future and that can really open up your shot potentials when working on visualizing your stories.
