This is probably not a new idea, but it only came to me today, and worked a charm. I have an old Wii permanently plugged into my TV, which I use occasionally to play SNES emulation. I realised that I could setup the SD card on my 3DS to function for the Wii too, just by copying a few folders and files and changing a .conf file or two. So now I can take my SD from my 3DS, put it straight into my Wii, boot up, load my favourite emulator (SNESGX) and wham - play my in progress blargSNES ROMs and saves from the same folder! Life changing stuff. Super Metroid in my pocket, and then when I am home straight onto my HD TV, without any hassle. Hoping this is useful to someone else. I am sure it could be repeated for WiiU or other systems that take an SD card.