Kuat is a pretty spectacular bike rack. It comes standard with two bike slots, but it can be upgraded to accommodate 4 bikes. The bikes can be locked onto the rack, there is even a built in stand to do minor repairs and maintenance such as drivetrain cleaning. It's on the pricey side, but you're an LX driver...
I tried to connect a link from Amazon but it was blocked. If you google Kuat racks, the first link on Amazon is direct from the manufacturer.