And how do I get a NAND then?
I'm sorry to say this but that sounds like a you problem.
If used Wii's are 400 dollars in your country then you could buy one off off me for 60.
I'll go to the used game store and grab one for 30, 30 for shipping ought to cover it fine.
There's so many options mate, being a dick on the internet about it isn't one of them.
Dump the NAND from a real Wii. I'm repeating myself here.
*Sigh* Why should used Wii consoles be banned from Wimmfi??? Though a lot of Wii consoles have homebrew software installed, this is still a tiny fraction of all Wii in existence. Surely not all consoles are defective.
I have no idea (never used Wimmfi) what gets a console banned from that free service. How likely is it when grabbing one of the over 100 million Wii consoles to get one that was used for cheating or whatever on Wimmfi? It is far more likely that some illegally shared NAND image available online is banned.
I literally bought Wii consoles for €10 (ten Euros -- that is not even worth thinking about).
To elaborate a tiny bit on this, Team Twiizers used to track the amount of homebrew installations.
I have a vague memory of them sharing some details that a million unique HBC installs have been performed.
Which was ~1% of all retail wii's at the time.
Like Sinchen said, it's impossible that all consoles are defective/hacked and banned.
Hell, you could even get a defective Wii (defective DVD, defective Wifi, missing covers w/e) and simply pull the NAND from it.