I bought nexus 4 in US and was able to use it without any simcard, but on wifi. I was able to pay at couple of locations and see tran history when wifi is connected.
Now, I am temporarily in the UK. Even before I inserted a sim card, googel wallet displays "unfortunately google wallet is not available....network" message.
So, this makes me believe that Google is using either wifi networks or gps to determine location and not allowing access.