As part of Google Compute Engine we provide an NTP server to the guest which is based on Google Production time. As such our VMs get to take advantage of this leap second smearing implementation. I was going to mention this at my talk at IO but forgot.
Yeah, sorry, I know they're the public DNS, but they're also jolly handy as unforgettable IP addresses you expect to be able to ping, hence the smiley.
Good news about the time{1..4} NTP servers, I'll give them a try, thanks.
I don't know about GAE specifically but I'd be very surprised if it didn't see the same time as the rest of Google. They would have had to do work to make that happen.