Hi lenny, sorry, I was busy working on my Tutorial, so it took me a while to answer..
Well, this is exactly why I told you to try and avoid turning Text into Meshes! Because the Mesh it creates is so horrible and irregular, any textures or particle system or whatever, appears irregular, as you can see here...
So you'll have to clean up the mesh of every letter, which can be a real pain in the ass!
After some experimenting I came up with this:
This is not straight forward and you will have to do a lot of tweaking to get the result you want, but there are many possibilities! This is just to demonstrate what's possible!
So, you will need Blender 2.78 for this!
Once again: do not convert your text to a mesh!
Now set your Feature set to experimental.
In the Materials Settings, set the Displacement to True.
Add Modifier Subdivision Surface and set it to simple and check Adaptive.
And then you can use a node set up, something like this for your Displacement.
You can of course experiment and use any Texture you want, also Image Textures!