A demo of the first Wii ELF loader is now available for download, thanks to bushing, Segher, and tmbinc. It takes advantage of the Twilight Princess savegame overflow from a couple of weeks ago, but now there’s something more substantial for people to try out on their own hardware.
Had my Wii not been stolen, I’d report back with more info, but from what I understand, this isn’t working correctly with at least one US Zelda revision.
You can track the latest Wii homebrew progress at the WiiBrew Wiki. From the looks of the video, these guys are probably very close to a bootstrap file that will load in an arbitrary homebrew application.