I admit that i don't really know that much about hacking consoles, but in theory, couldn't you write a custom driver for your WiFi adapter in your pc that allowed it to act like a 3DS offering a download play game, but was really an injected version that ran unsigned code or something like that? This way wouldn't require any extra hardware. I know this was tried at one point on the DS but what you could do with it was very limited because of the size of the amount data the DS could store. But with the larger amounts of data being able to be stored on the 3DS, wouldn't it be alot easier, and possibly we could run a piece of unsigned code and have a softmod from there allowing code to be run from the SD card slot? I know its probably alot more complicated than that and it is probably encrypted or something along those lines for protection, but its just an idea.