With Gamestop selling out everywhere on their limited stock, and Amazon holding the exclusive until September 1st in the major retailer section, we have to look elsewhere for Discord, Celestia and Nightmare Moon's initial Guardians of Harmony release. The trend seems to be favoring small stock at various stores that don't usually carry pony merchandise, for their "pop culture" sections.
Barnes and Noble is the most recent one of these, with all three appearing at stores across the USA. You now have another alternate location to scoop them up at!
Thanks to Katney for the heads up.