Yesterday, the Nexus 5 was available to “ship from warehouse in 1-2 days” from Google Play. Today, it’s out of stock in all colours and sizes. Same goes for the Nexus 7 and Nexus 10.
Update: The 32GB Nexus 5 is still in stock, but that’s likely an oversight. Do not buy a Nexus 5 today, please. Unless, of course, you want a Nexus 5.
Update #2: OK, @daveloft made a good point in the comments. Perhaps Google knows that the Nexus 6 is going to be too big for some people, and plans to keep the 32GB Nexus 5 in stock indefinitely to appease those wanting a smaller device. It’s likely not an accident that the 32GB Nexus 5 is the only Nexus product currently available on the Play Store.
(Thanks to everyone that sent this in!)