Have you heard about MicroCore Labs' FPGA implementations of retro CPUs? Check out the blog with a lot of interesting details and photos, there are also links to YT videos which show how these can be used as drop-in replacements for original CPUs. Recently one of the cores has even been open sourced.
It will be interesting if someone can do a 100% cycle-accurate 8088/8086 to run some of these old games that basically flip out when run on something too fast. Case examples being software designed for the PCjr/Tandy 1000, and original IBM 5150 PC model where they basically blow up on anything faster. (Ultima 2's divide by zero error being the one that comes to mind, but there's plenty of other games that simply run too fast, or emit hissing sound/noise instead of beeps because the PIT is too fast)