I wanted a locking surfboard rack for my Nissan XTerra and turns out Yakima Racks and Thule Racks don't have lockable surfboard racks. The Thule 554XT surfboard rack does mount to the Nissan XTerra crossbars and is pretty inexpensive but again it doesnt lock the surfboards. So after asking around someone turned me onto the Inno Racks Surfboard Locker rack. It works on my XTerra bars nicely and it has a very sweet integrated surfboard locking system that locks both of my surfboards, yeah it carries two long boards. FYI, I got it here...
http://www.orsracksdirect.com/inno-racks-boardlocker-surfboard-rack.html