Bamco just announced it via Twitter:
https://twitter.com/BandaiNamcoUS/status/613255236820414464
Only for the Americas right now, but since we had that "leaked pic" of a poster at a Spanish retailer, European release is pretty much confirmed too. And since it's the same date, well...
PR:
Dragon Ball Z: Extreme Butoden is coming to the Nintendo 3DS on Oct 20th in the Americas!
https://twitter.com/BandaiNamcoUS/status/613255236820414464
The EU confirmation actually came a few minutes earlier than the US one
Oct 16th
https://twitter.com/BandaiNamcoEU/status/613253411920855040
PR:
DRAGON BALL Z EXTREME BUTODEN to be released in Europe, Middle-East, and Australasia
Goku and His Friends Are Back!
BANDAI NAMCO Entertainment Europe is proud to announce that DRAGON BALL Z EXTREME BUTODEN will be available in Europe, Middle-East and Australasia starting October 16th!
Developed by the famed Arc System Works teams, DRAGON BALL Z EXTREME BUTODEN contains tons amazing features bound to energetic and visually attractive fighting-games! With 20 playable characters and more than 100 support characters, fans will be more than happy to look for their favourite team composition and duke it out!
“Following the success of DRAGON BALL XENOVERSE, we wanted to keep on bringing awesomeness to our fans and make them as happy as ever. BANDAI NAMCO Entertainment Europe is listening to fans and will keep on surprising them over the next few years! In the meantime, everybody will enjoy a high quality fighting-game based on one of the most emblematic Anime & Manga ever created!” said Herve Hoerdt, Vice President of Marketing & Digital at BANDAI NAMCO Entertainment Europe
DRAGON BALL Z EXTREME BUTODEN will be available in Europe, Middle-East, Africa and Australasia on October 16th only for Nintendo 3DS™ and new Nintendo 3DS™ systems!