My next #RC2014 / #RCBus module is now listed. This is a #Z80 based module that dynamically boost the CPU speed to 20Mhz when not doing any I/O - so lots of compatibility with stock Z80s modules - but a little bit faster.
No need now to be a slow dinosaur.
More details on my website: https://www.dinoboards.com.au/stegosaur/turbo-cpu/