The MC-12 has an ISR mission, and they started development last summer. According to a Global Security article, "SAF/AQ tasked Big Safari to procure and modify aircraft as quickly as possible." They're flying operationally now. Nice!
The C-27 is a "mini-Herc" (a smaller version of the C-130 Hercules). It too is a rapid development effort based on a mature airframe. Very, very FISTy.
I hope we continue to see more efforts like this!