It's more an on-paper iHac Pro, because it hasn't been build yet and it's unclear if MacOS will boot. Looking forward to hear if/when somebody builds it.
As for installing a i7 8700k: I'm certain that no kext's are out that support the chipset.
You're absolutely right that it's an 'on-paper' build. I did make sure to check each component, that they have been used successfully in other Hackintosh community builds, with High Sierra.
If it does in the effect the final image, that image just gets a rerender... but its rare that it actually is noticeable.