We were at the Best Buy on Regent, so it was probably close to there. What he did say is that people were being hooked up were in all parts of the city, he wasn't any more specific.
As for the Gateway, he said it replaced the old STB with the built in gateway, and it served all the new STB's in the house. I looked up some information on the 2wire website, and it appears that the gateway is required, and that all the STB's plug into it. It also has a built in Router (both wired and wireless) as well as a firewall. I scanned the user manual for the gateway (there is a 130 page pdf on the website) and it seems to be a rather good firewall.
I would guess you could probably attach your router, then move the router to the DMZ of the gateway to bypass it, but I am not sure there would be much point.
That is about all I know, wasn't a very long conversation with the guy, but enough to get me excited about the service.