The device was bought by Japanese WP7 user @Pandora_Grani from Yahoo Auctions Japan. The seller claimed to have bought it in Shanghai or Hong Kong. While the phone appears to think it’s been set to English language, the text all over the phone (apart, strangely, from the Music & Video hub) is in Chinese. It’s suspected that this was made by ROM hackers at xda.cn. If this is an amateur effort, it’s an impressive one (though as I can’t read Chinese I can’t tell how well done or useful it really is).