If you don't find any pre-made, you could always use a fine grade steel wool or sandpaper on them. I've seen it done and the finished product looks just like brushed aluminum. You start out using small circular motions and finish in a single direction. Its a little tedious since you apply very VERY little pressure with quite a bit of rubbing so as to not cut through the chrome layer into the plastic underneath. Basically you are just scratching the dickens out of the surface until the shine is gone.
Just something to consider if you can't find what you are looking for.