Do you have any idea what it means to repartition a drive? Rhetorical question, no need to answer that. Creating the emunand partition without deleting any files is just not going to happen. It would be a pain to do on a PC (but possible... but why when it's easier and much faster to copy-> repartition-> copy back?), let alone on the 3ds.
The most you could ever hope for, but still unlikely anyone will want to bother writing the code, is the ability to inject an emunand backup into an already-made emunand partition. Perhaps flash a sysnand backup as well. But again, not likely. Especially considering how dangerous it is and Gateway's launcher already handles the sysnand perfectly.