Adding reflective highlighting to materials in SketchUp

We are thinking of adding some tileable overlays to images as part of our Textured Material Wizard - to add to our Make Tileable routine and our upcoming Match Color routines.

The idea would be to merge a pattern of color or intensity with an existing image - much like SketchUp includes some cloud reflections in their window materials. We would add the highlighting to the SketchUp material, but remove it before rendering with nXt.

Does anyone have any experience doing something similar in PhotoShop or CrazyBump?

And, in particular, is anyone aware of any repeatable patterns which we could use for this? (not just reflection like highlights - but also other things which are useful to super impose over an existing texture image)