So far all I've been able to find out are some of the dates of the invitational millionaire qualifiers in AC. Ballys is having one on April 8th. Harrahs and Showboat will each be having one on April 29th.
Link Here's the AC Harrah's link for the WSO21: http://www.harrahs.com/our_casinos/atl/gaming/wso21.html
Harrah's AC Events All of these events are now posted in the Event Calender https://www.blackjacktournaments.com/tournaments/ Also posted under the individual casino listing.