According to @evleaks the reason we have not seen this handset in the U.S. yet is due to the fact that this is a specific variant of the phone (LTE-Advanced). Reportedly, the device will come under the Sony Sirius Viv (D6503) name and it should arrive during the middle of next quarter.
Verizon customers: your wait for the Sony XPERIA Z2 will not have been in vain. The delay, if you want to call it that, is due to the fact that a very specific variant, one that supports LTE-Advanced, must wind its way through the certification and testing processes. Look for the Sony Sirius Viv (D6503) during the middle of next quarter.
Are you interested in either the Sony Xperia Z2 or the tablet variant of that phone?