In addition to Edison breakout board, there are also a number of expansion boards available through Sparkfun. (Please see this link ) You access functions such as I2C, micro SD, ADC etc. using these expansion board. They also provide the flexibility of connecting to one another like a set of lego bricks that do not exceed the form factor of Edison. Although the lead time on those boards are 6 to 8 weeks at the moment, it is definitely worth placing an order now to get those as soon as they become available!