I use a generated texture for the displacement modifier, but then I want to use it in Cycles for the material as well.
Is there a thing such Texture node?
No use Image node becase I won’t load any image. I want to load the auto-generated texture.
These are the textures you can add
I fully agree with Richard Marklew, but to help you understand more watch this:http://www.blenderguru.com/videos/create-realistic-materials-with-cycles/
This is what I want to do, but not in the RenderLayers but in the Material.
Do you think I should export it in proper dimensions and then load it as an image?
Also do you consider it a good idea to open an issue in blender developer list?
Hmmm… Actually, that’s a rather neat way to export a procedural texture that I hadn’t think of… yet.
And, yes, for the moment, that’s a workaround for some blockades on the path of the textures with Cycles. As you just found out, Blender Internal’s procedural textures can’t be used in a Cycles material node tree. Some modifiers open the door but the node tree slams it back into your face very quickly. 
As for talking about it to the devs, it never hurts to ask. The answer might tho. Choose your words carefully. Avoid “bug”, “issue”, “problem”, “trouble”, etc. Be positive! The devs are dangerously nervous entities and you might end up on a stake. 
Hehehe. I tried this thing several times.
But i am not good at creating procedural textures 