As a result of the combination of WP and SM, I also had >1 million qualification miles. Based on the OP's posting, I went to the website, entered my PIN and got:
Congratulations! You've earned a new Million Miler status in our SkyMiles program. We'd like to thank you for reaching this elite level—and for flying Delta. So it's on us; we invite you to select a gift that's perfect for busy travelers and for those who like the finer things in life.
So I picked the Tiffany cuff links. Maybe the 2-million-mile mark will have a shirt with French cuffs as an option...otherwise I have to go out and buy one!
