Being the world's biggest online shop, I think it's really strange that Amazon doesn't have the Wii U console.
I almost always buy my consoles on amazon, because where I live they are terribly overpriced.
Mind you, this is not like the Wii that was "sold out" for a long time, amazon simply never had the Wii U.
Something may be going on between amazon and nintendo regarding consoles, because amazon never received the 3DS XL either.
The last console amazon had was the regular 3DS (I bought it there a couple of months after launch), but now amazon hasnt received new units of the regular 3DS either...
If you go to the "Buy Now" section of the Wii U on nintendo's website...
http://www.nintendo.com/wiiu/buynow/
...it has links to several websites (bestbuy, walmart, gamestop, target, etc), but not to amazon.