Atari

The MiSTer FPGA Jaguar core when run on a system with dual-RAM is a suitable substitute for a real Jaguar because it is effectively cycle accurate.  The single-RAM core is still pretty good too.

I had heard about this years ago but it seemed sort of fishy... so glad someone got the story and documented it quite well... even if it had been sitting there for 6+ years before I discovered the video.  Enjoy!