Nintendont is more of a virtual machine/sandbox, as far as I understand. It doesn't need to emulate the Gamecube CPU at all; it merely provides an environment that GC games like for the most part (faking how much RAM is available, redirecting memory cards and the DVD drive to sd or USB, patching certain parts of the games so they run at the correct speed, etc.). Since the N64 and PS1 use completely different CPUs (both use members of the MIPS family) than the Gamecube and Wii (these are PowerPCs), it's necessary to emulate them, so no, it's not really possible to provide a Nintendont-like homebrew for those two systems on the Wii.