You are right, probably it can be emulated on its final form, but SF3 is constantly evolving, and it is formed by a CPLD(Complex Programmable Logic Device) and a lot of modules(Sound, RTC, Wifi, USB, Memory) on a I2C bus governed by an ARM processor with its own program.
SF3 is like killing fleas with cannon shots, a lot more powerful than the machines on which it can be connected. But its main characteristic, what makes it less "emulable" is that it is not made with fixed electronics, at least the CPLD, the Arm and the Wifi module(also based on Arm) can be updated with new firmware.
Think on a new fascinating and necessary characteristic for the SF3 and Hans will struggle to put it inside(but first he has to finish the interfacing on the 4 computers).
For example, on the CPC side there is a development to install disk images, it will be the Arm code who will move the "disk image engine". We "Enterprisers" don't need such thing, the Enterprise doesn't have protection schemes on commercial disks(neither even commercial disks....). We have always managed plain files. On the SD we have files, not images, and the HxC and Gotek floppy emulators have not been very successful on the Enterprise user base.
Every computer(CPC, EP, MSX and PCW) has its own CPLD and ARM firmware. Some characteristics are shared, others not.