Regarding the size of the board: have you considered BGA package? I guess that could be a significant increase in assembly price (x-ray and stuff for bga), and definitely not quickly-handsolder-a-proto friendly, but still...
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
Regarding the size of the board: have you considered BGA package? I guess that could be a significant increase in assembly price (x-ray and stuff for bga), and definitely not quickly-handsolder-a-proto friendly, but still...