They’ve been out of stock at Best Buy, Gamestop, Toys R Us, and just about everywhere else you can think of, but I’ve noticed that in the last few days there have been a couple Wii U’s at Walmart. If you’ve been trying to pre-order, check them out.
Here’s a link to the Deluxe Console. As of this writing they’re sold out online but a few locations still have store pickup available:
Here’s a bundle that had been available, but it’s going in and out of stock:
Finally, here’s a link to Walmart’s page for the regular Wii U, although this has been out of stock for a very long time.
Check these links from time to time, as Walmart has been the only retailer that seems to have any kind of Wii U’s available at all. Good luck!