it is already as beta, but never be in the public. You need to buy it from the pretendo go to donation ( log in on you PNID account ) then chose the Super Mario or Mega Mushroom for the beta server (you need to buy it with credit card or use and login Link for third party)

by the way im not a worker from pretendo but i wish i was

but Wii U Chat is at 85% finish but again it will not be in the public