If you own the Sony Xperia Z (C6603) and are based in Canada, then you’ll be glad to hear that there is a way to get LTE to work. The method involves downloading the FTF firmware file for the Xperia ZL (C6506) which is the North American variant. Users then flash this firmware’s baseband onto their Xperia Z using Flashtool (see what settings you need below). Users are reporting success with carriers including Rogers, Fido and Bell. If you want to give this a try, there are some detailed instructions here.
Flashtool FTF settings