http://code.google.com/p/open-wiiflow-mod/source/detail?r=8I've always thought it would be cool if Wiiflow could have done the same thing with homebrew, too, just grab the HBC banner and tack it onto a temporary Wiiflow box.
You can download HQ gamecube covers already directly via wiiflow
Wiiflow only works on real nand as well as the DML functions currently (but overjoy will help with emu nand soon