Great project and write-up. I'm reminded of a couple other projects.
MC Hammer project for LLVM tests round-trip properties of the ARM assembler. http://llvm.org/devmtg/2012-04-12/Slides/Richard_Barton.pdf
Sandsifter x86 fuzzer. https://github.com/xoreaxeaxeax/sandsifter https://youtu.be/KrksBdWcZgQ