I would like to present you a project that will be crowdfunded soon:
It is a very small footprint board that incorporates an Atmega 644 / 1284 MCU. I originally designed it because I love the Nano, but I needed more resources to run some OLED and TFT displays and was not satisifed with available alternatives. I could not find it on the market though it might have existed in the past (but without USB as far as I could see).
The design is a common and relatively simple one. The hard part in this project is the QFN assembly and the baking of the double sided board. So I will probably ask a chinese manufacturer to assemble them.
I will be glad to reading your constructive comments!