Is there a way to get a visual output of a procedural texture within cycles?
This would greatly help with making adjustments by seeing the flat, greyscale result as a texture is adjusted.
Also, is there a way to keep cycles from restarting real time rendering every time a node is added or deleted even when they are not hooked into the output?
In Cycles, the material adjustments tend to be made in the rendered view, if that is too slow, you can speed things up by doing things such as isolating the object being edited in its own layer so it’s just rendering that object (though if even that is slow, there are plans that indicate that performance improvements are coming very soon and thus will likely be in 2.64)
On the second question, I don’t think there is a way as of now.
To get a grayscale plane result: create a plane, apply the material you are editing to it, and render that. It creates the same general effect, albeit still is slow due to Cycles…
Zoom border does not work on camera viewport shading set to rendered, but as a UV image “render result”. Zoom border (Shift-B) a region in your camera viewport, render (F12) camera, view in UV image mode as “render result”.