Just ran some numbers and that Sony phone would be about 109.24mm tall and 57.88mm wide. Compare that against the 123.8 x 58.6mm iPhone 5.
IF this is Honami Mini then Sony are bloody wizards for being able to achieve something like that. Thickness is the only unknown factor. Sure it could be a low/mid range phone, or this could be a hoax... All the insiders seem to believe Honami Mini won't be seen until December at the earliest. What're the chances it'll be seen as early as IFA?