I found out that the Nikon D600's custom settings can do something that Nikon pro bodies can't do: the custom settings can store the metering mode.
The Nikon D600 uses a button + dial combination to change the autofocus mode (from AF-S to AF-C to AF-A). The same is true for the D4 and D800. However, it also uses a button + dial combination for the metering mode (from matrix to center to spot) whereas the D4 and D800 use a dedicated dial.
Because the D600 uses button-based controls for the autofocus and metering, it can include the autofocus and metering settings in the custom settings. In my case, I've set the U2 custom setting to spot meter with a +2.7 exposure compensation. That way, if I want to just meter for the highlights for a contrasty scene, I can just switch to U2 and spot meter off the brightest highlight. Then switch back to normal matrix metering after that.