Good point. I hadn't considered it from that angle.
I could note that modmii can build a complete nand from scratch, but being able to mess with your own dump is a much cleaner solution*. Otherwise, you'll have to use savegame manager gx to extract your savegames and miis, programs like wii mod to pack the installed channels as wad and take a note of your system's settings...and then use all that data to almost manually get it all on that precreated emulated nand.
*the pun in this sentence is intended.