Mech, this is also worthy of consideration:
20x12 bit adc, 256 KB Flash, 16 KB RAM, arm m3 core $7.88 at mouser
32L100CDISCOVERY for STM32L100RCT6, $7.88 at mouser
EDIT: they also have an arduino looking thing ($11) that might be easier to get started with, *should* have like 40 ADC pins, but arduino may not have caught up with that sort of expansion:
http://www.mouser.com/Search/Product...-NUCLEO-L152RE