The GSBarnDoor project, also called just "Barn Door" or "IIgs Barn Door", was a collaborative project between James Littlejohn of 8bitsystem.com and Henry of ReActiveMicro. Henry's involvement started in May of 2011.
The project was supposed to be a CPU replacement for the Apple IIgs. Henry was contacted since he had contacts at VLSI Concepts (http://vlsi-concepts.com) who could provide a licensed, working core. Henry and the owner of VLSI Concepts would work together to provide a working CPU replacement based in an FPGA. James Littlejohn and Henry would then use the CPU replacement design as a bases for the GSBarnDoor project.
The core that VLSI Concepts was providing did 8bit, 16bit, and also 32bit processing. They completed their IP core around November 2011, and it has been available since then for license.