I don't see why you are having such trouble, the wad files are out there, you just need to look.
For example if I wanted the Snes9x emulator channel to be installed all I needed to do was type in "snes9x channel" and the first link that came up that wasn't a youtube video featured the download.
As for VC channels there are repositiories here on this very site and I'd imagine channels for everything else if you had a mind to look for them.
Me, I can't be arsed with so many channels as they clutter up things. How often do we actually use Wad manager and is it really worth having it wasting your Wii NAND space when you could be using it for games?