I bought one in Arlington, TX (just west of Dallas) today from a Best Buy. I used their website to verify they had a 16 GB Wifi in stock. Their website it pretty handy. All stores in the area showing out yesterday then about 30 minutes after they opened, two stores showed to have models in stock.
Keep checking their websites.
I listed at my Apple store for a 16 GB Wifi model 10 days ago. Still nothing. True I could have ordered off the website. Bleh.