Folks have been doing this for years, and for cheaper, with balloons and kites. Check out the awesome work at publiclab.org, where they've mapped the gulf oil spill in 2010, pollution at the Gowanus canal, Occupy encampments. Stitch the photos with the OSS Ruby tools at mapknitter.org, publish them with a public domain license, and they'll actually be added to the google base map!

Buy a kit for < $100: http://store.publiclab.org/products/balloon-mapping-kit