Bank of the Ozarks is advertising a 4.07% APY on its Investor's Choice Money Market Account. The minimum deposit is $10,000. It doesn't seem to be listed at the bank's website. It was advertised in today's Dallas Morning News. The ad is available online here. The ad states that the yield is subject to change, so there's no guarantee how long it'll last.
This special money market rate is only available at their branches in the cities of Frisco and Lewisville which are in the Dallas/Fort Worth area. The bank is FDIC insured (Certificate # 110).
Thanks to the reader who emailed me info on this special.