Eh? You don't need a prebuilt SD card image. I'm sure you had some emulators you liked and some you didn't, and almost certainly you won't get the same selection from some random person. For instance every Wii I put together I only put FCEUltraGX and Snes9xGX on, IMO the rest is crap.
Just put together what you want yourself, Google Wii+emulator+whatever system you want, and find the latest/best version of the emulator. Copy/paste that into the apps folder on your SD card (or whatever the installation instructions are) and take a look if we have a romset for it (we probably do, >here<).
