The design and the buttons is not a big deal with copyrights unless you fully copy everything exactly. If buttons are similar, but not the same, bezel looks like, but not the same, and of course the name of the device is not a commercial name, then is fine. Again, imitating the look is one thing, an exact copy of the design and even the name is different.
The real issue is when, aside the bezel or the buttons, the functions, instruments and the screens elements and procedures are also a copy. This is why you will not find functions or instruments in SkyElite or SkyScout that look exactly of how commercial EFIS look like. My products are more focused in finding a solution for a simulation tool than a replica of a real thing.
Some customers complain about this.... why this is is not a G999? why it does not look like XYZ? Simple: because it is a $20 product.
There are a lot of G1000 trainers in the market, software only products are always $800 and up... that is for a reason.
Going back to your point: even if I develop a configurable drag&drop EFIS system... I still cannot copy instruments, functions, elements and procedures. It will never be similar to a real thing.
And now the most important thing.... I spend a humongous amount of time supporting users because they don't know how to type http address on a browser, not how to find the IP address of the main computer or how to make the browser full screen. Imagine providing a drag and drop empty solution to fully configure.
As an user passionate in flight simulation, instruments and cockpits I totally understand and love your point. When I have to think in the sales and support side of this... I simply don't see it without dying on the attempt.
Please, don't take me wrong, this is not a negative to your proposal, which is still very interesting.... it is just I have to think a lot about this, and if it's worth it or not, because there is a lot in the back stage.
More soon!