I picked up the first season, and I favor the theory that, much like the taxi chase in Attack of the Clones was based on some guy at Lucasfilm's game of Crazy Taxi, Girls und Panzer is based on some guy at the studio's game of World of Tanks.

World War II tanks surviving into the modern day, the richer schools like Saunders and Pravda fielding up to 15 tanks (most WoT battles are 15v15)... tell me you don't see it. :)

-- Slider Da Feral (NYAR!)
www.worldoftanks.com for further details