Bus Pirate 3 -> 2x AVR (ISP) adapter!
This is a really short post since the actual pages have more information. However, Avrrrinator B is now out the door. While my personal use cases have been quite limited (burning bootloaders for Arduinos, flashing blink programs/not learning my lesson with RSTDISBL), hopefully someone will find a bit of utility with this breakout.
For more information:
The Eagle source/Bill of Materials can be located here on GitHub.
The long form blog posting is here.