Day 1 Studios, them fellas behind F.E.A.R & Fracture, had been working on a Batman game: Batman By Gaslight, based on the comic of the same name. The game would position the caped crusader in a steampunk vision of the 19th century as tracks down the (near mythical) serial killer Jack the Ripper. The game was designed as pitch by Day 1 for the Xbox 360 and PS3 back in 2009/2010. Sadly the game itself will never see the light of day, but with some animation prototype footage we can now mourn the loss with a bit more visual flair.
Thanks to Siliconera for the info.