While far from official, one European retailer has outed November 13 as the day the PlayStation 4 will be available in Europe. The only official launch date we've received from Sony is that it will launch for $399 sometime in 2013, likely towards the holiday season.
According to some user reports, Media Markt employees actually confirmed the November 13 date with customers. While it is possible the store knows when the console will launch, it probably is more of an educated guess simply because Sony wouldn't be too happy with them posting the date up.
The Wii U launched last year in November and November makes a great time for a launch as it is 4 to 8 weeks before Christmas. This would allow time for parents to shop for their children. As with all unofficial reports, take this date with a grain of salt.