Could the gateway spoofing not provide a solution to this though? I mean they can Spoof firmware, and region why not the ability to just say something is something it isn't. (ofc i have no idea how there system works, just speculating here.)
An example.
Scenario: I take a normal 3DS with the system ID of say 1234 with game X and Y on the SD card downloaded from the store. My friend has a system with an ID of 4321 and wants games X and Y.
Idea: Now I don't want to just "give him" my games we both want them. So he gets his Gateway 3DS inserts it into his console what has the system ID 4321 and he changes his system ID via a spoof hack on the Gateway 3DS. So now we have 2 systems #1 is mine with the system ID of 1234 and #2 His with the system ID of 1234 (spoofed via Gateway 3DS). Now we take my SD card place it into a computer and clone the SD card. Now we have 2 matching SD cards. We place one of these into friends system and the other into mine.
Now mine boots up fine (nothings changed so this is expected). His boots up nothing shows up and he does a system restore in Gateway Mode with the spoofed System ID (the same ID as mine) and hey presto! Games restored. 2 Consoles, both with same id although 1 spoofed and same games. As far as Nintendo are aware the systems are the same.
Now we could take this further by people sharing there SD card contents online and system ID's.
Would that not work?