Do they actually ship from their office though? Or from a warehouse somewhere further away?

I think their warehouse and office is in the same place.

The Adafruit offices are in NYC, right? There are three or four Microcenter stores in the area, and they claim to have "10+" available.

Interesting. I went to Microcenter once and got a tablet for $20 bucks. Nothing fancy though...had Jellybean installed. I will definitely check them out for the pi zero...hope I am not too late to the party.

On their website, you can choose specific stores and get inventory counts for that store. Of course, I'm making the assumption that the numbers are correct-ish. Every one of their stores that I've checked always claims "10+" Pi Zeros in stock.