This isn't UPS problem. I work for UPS and we use different system to track within our hubs/warehouses to track each package/letter. I just checked this morning in my local hub and it showed no sign of Google warehouse (located in Louisville, KY) actually dropped off at their local hub. Just like anyone can create shipping label doesn't mean they guarantee to drop off the pkg at the hub. For 2nd Day service, they can still use either plane or ground trailers to transport your package. Once your package is physically dropped off depends on local pickup time or processing time, UPS would physically scan each package. After that process is done, prior to transporting your package to other hub/warehouse to further process to the final destination, it can take up to 1 hour to show any movement online where everyone else can input tracking number.
I first assumed Google forgot to ship mine, in which my experience big company like Google can easily do while processing possibly thousands of nexus 4 across America, however, I just found out you guys experience the same. I guess we will have to wait and see what happens next.