Actually, what you describe is the most common way. Associate the dimensions with a layer and hide or show the layer as needed. I use this technique frequently since dimensions are usually useful only from a particular viewing direction, otherwise they foreshorten or hide behind geometry. I make a scene for each direction for which I want dimensions, create a layer visible only on that scene, and associate the relevant dimensions with that layer.
By the way, dimensions are one of the few exceptions to the usual advice to never associate anything but groups or componentinstances with any layer except layer0.