Even if Apple did not officially announce the change at yesterday's September event, they completely eliminated the 16 GB iPad versions from the Apple store. The entry level models all start with 32 GB of storage now, the iPad Pro's top out at 256 GB.
http://www.notebookcheck.net/Apple-iPad-series-Apple-bumps-up-minimum-storage-capacity-to-32-GB-intros-256-Pro-models.173737.0.html