There is a project to detect lightnings over Moscow with cheap sound-only detectors on the roofs of skyscrapers, they managed to restore ever shapes of lightings in 3D with it:

http://habrahabr.ru/post/211701/ (description of their technology in Russian)

http://flashlook.ru/ (official site, no realtime translation now because of lack of funding, there are some prerecorded lightings)