The question isn't that far-fetched actually - writing an emulator for 70s style embedded hardware to run existing code is certainly much less work than coming up with the corresponding equivalent of said software from scratch - sooner or later, you would hit a breakeven point, just look at the plethora of existing c64 emulators so that people can still run all those old arcade games, or all those 8086 and 8051 emulators.
The other question is whether source code (or even just bytecode) of the corresponding avionics is ever going to be made available, and if it is made available, whether it will be in a form that can be adapted for these purposes, i.e. there's more than just the CPU/micro-controller to be supported, there is usually tons of embedded hardware, which isn't as easily emulated.
As a matter of fact, I think I already mentioned this once: at some point (as in a decade ago), the highest fidelity GPS device available for FSX and X-Plane was the Garmin GNS 430/530, and what they're really doing is running the freely available Garmin GNS trainer (simulator) and hooking it up to various FSX specific internals (think position, altitude, orientation, velocities etc), while capturing the output of the device and displaying it as a texture in FSX/X-Plane respectively.
Quite honestly, you cannot get closer to the real thing than using this approach...
Note that this "simulator" (trainer) actually runs a subset of the original firmware of the real device, i.e. is commonly used by pilots for familiarization purposes, and by developers for testing/developing features, which also means that it does contain a corresponding AIRAC cycle (navdb equivalent in FG).
Thus, the idea/approach really is very sound, and at some point much more feasible than re-implementing such software/functionality from scratch, especially given the time, skills and expertise required to read up on all the specs and then re-implement those; in comparison, implementing an emulator (or even a simulator) is much less work in comparison, and much more self-contained, especially for people with a CS/SE background who are familiar with compiler construction and VMs.
Given that many others around here don't have Thorsten's background regarding maths, physics and spaceflight, the VM/emulation path would be the only sane option under different circumstances.
http://www.reality-xp.com/flightsim/gns530/http://www.mindstaraviation.com/product_430_530.htmlhttps://www8.garmin.com/support/downloa ... sp?id=3529https://www8.garmin.com/support/downloa ... sp?id=3531