Bent Reflection on glass glazings

There is uniformity with glass surface because of warping and unevenness like the image below.

I was challenge to produce this type of warping by one of our blog reader- how to produce this type of effects. Honestly I dont know. But I tried bumping it with no success, in the end i have to use displacement.

















I created a displacement map like this in photoshop

I am still not happy wiht details, but i feel that its doable. Here is my preliminary test render.