I don't know if it already exists, yet if not someone should invent an electronic nail puller for. Useful on large roofs in need of replaced plywood or osb, a nail puller shaped like a Colt model 1911 with a powerful new battery instead of a magazine- or perhaps like a grease gun, would punch into the wood in a circle (adjustable) around a nail head to a depth of a quarter of an inch, tighten and extract- perhaps ejecting a nail like a spent cartridge.
A semi-auto nail puller would be a useful tool.
