My guess is that it is made in China. As mentioned by the OP, it uses an ATXMEGA32A4 32KB Flash, 4KB SRAM and sells for $49. The 128x64 OLED display is definitely made in China is available on FleaBay for about for about $5-7 such as here 128X64 OLED LED Display Module

A local (USA) vendor also has it ($3.10/1,000) CFAL12864N-A-B1


Here is the same display used in a $19 MP3 Player USB Rechargeable 1.0" LCD MP3 Player - Red (2GB)