Update: Google says the Nexus 4 isn't sold out, but that the Play Store is just being inundated with demand. Here's what we're seeing on the Nexus 4 page right now:
Google Play is currently experiencing very high traffic. Nexus 4 is not sold out and will still be available for purchase. Please try again shortly. Thank you for your patience.
It's no secret that Google didn't handle the Nexus 4 launch as well as it should have. There was a problem with the system, orders got lost and/or cancelled, they sold out way too quickly - the whole thing was a complete mess. Hell, we didn't even know what time they were going on sale the first time around (I got up at 2AM CT thinking they would be available starting at midnight PT. I was wrong). Like I said, it was a disaster.
Now, however, it seems that Google has it figured out. They sent out notifications this morning to let potential buyers know that the device would be back on the U.S. Play Store today at Noon PST. That in itself should lead to a much smoother buying experience for everyone who didn't get their order in the first go around.
The time of judgment is now - the clock just struck 12 noon on the west coast, and orders are once again live in the Store. It looks like both 8 and 16GB versions are in stock right now - let's just hope Google actually has enough to go around this time.
Good luck and Godspeed, my friends.