While Perron later backtracked a little from his comment, it doesn't matter. Other rumors have Sony starting a test run of several thousand Windows Phone handsets. It is expected that the Sony phones will be the first to roll off the assembly line with the new GDR updates being planned by Microsoft.
Besides producing devices with Windows Mobile, a few years ago, Sony Ericsson had manufactured a prototype of a phone that ran on the Windows Phone 7 platform. Codenamed "Julie," the model never did get offered to the public.
source: @tomwarren via WMPoweruser