It looks like Sniper Elite V2 will be getting some zombie themed DLC, or possibly a standalone extension in the form of Nazi Zombie Army 2, if the teaser Rebellion currently have up is any indicator. The image URL ends with NZA2_Newsletter_teaser.png, so that’s a pretty big clue.
It also looks like Rebellion are considering launching Nazi Zombie Army 2 on the next generation of consoles too, as the question on the teaser site asks what a player’s favourite platform is. The options include the PS4, Xbox One and Wii U amongst the current Xbox 360, PS3 and PC. Then again the Wii is also mentioned but a release on that seems slim.
The original Nazi Zombie Army looked at an alternate history where Hitler raised the dead to fight the allies. It received some average reviews. If you’re interested in signing up for news to the supposed sequel then you can sign up here. And if you do then you get a digital copy of the Nazi Zombie Army soundtrack.