Because winters are sucky and the weather outside still not at all inviting, I decided yesterday to see how close you could get to making an Arduino Pro Mini with through-hole parts. The answer is about this close.
The main differences are the final product measures 1.1″ x 1.8″ rather than 0.7″ x 1.3″, two extra analog inputs available on the SMD version of the ATMEGA328P are missing, and the low-power configuration is a build-time option. Here’s the schematic* as it stands today.
If you’re feeling brave enough to build this thing, PCBs are available through OSH Park.
*Subject to change!