Looks like we finally found out what that
vague talk of more Strike Witches was all about. As it turns out, it wasn't for a new TV series or an OVA, but rather a Strike Witches movie! The news was announced during a Nico Nico Live stream, & then confirmed from SW creator Humikane Shimada on his Twitter account.
More information should be revealed in the next issue of Nyantype magazine, but a 2011 release seems like a safe bet. We also await to hear whether it will be a continuation of the first two seasons, a retelling, or just a long clipshow with a few new added scenes. Personally I'm going with a continuation. Whatever the case, when you combine this news with the also recently announced
K-ON movie, it's clear that moe anime fans will have a lot to look forward to at the theaters next year.
Source:
http://www.animenewsnetwork.com/news/2010-10-28/strike-witches-gets-theatrical-film