I hit MM around the start of the year, and since then the options have dwindled. Back then it seemed like some of the Tumi options were not the most recent version, so I was holding out for newer ones, and maybe for a USA-sized carry-on. (Delta offered the international-compliant carry-on. I checked it out in a Tumi store, and it's noticeably smaller than the domestic version.)
I also e-mailed Delta and received written confirmation that there is no deadline to choose the gift.