Manga/comic material , Specular instead diffuse?

[MaloneXI]

Hi all,
As part of a job, a comic book project , I'm still looking for a manga style material. As many others I think ^^ I would want an artistic direction very close to manga we all use to see , or something totally different , as BLAME! or theses kind of things.

Applying a toon material on a simple mesh is cool, but it simply draws line on each part of the mesh :



What I would want is keeping somes details on textures, close to the diffuse channel.

And yesterday, by mistake , I put the specular channel instead of the diffuse one. And , for now, I don't k,now how to improve it , but the result looks really close to what I want :



Sure, if I post-prod the 2 pics on photoshop, it gives something reaaaallly cool, very arty , very special:



So, you doubt my question ... Is there a way to desature the diffuse channel, to modify its contrast to obtain a similar result ?

I'm asking for a simple reason : lazyness. "lol".

If not, I have to modify all the diffuses on toshop, and replace the files to make keyshot understanding it has to use the new spec textures, of put the spec texture in the diffuse channel manually.

You can understand that , having a big city modelized , I will not have fun at replacing all the materials...

What I would want to learn , if that's possible hu , is a complex node system inside de material tab , to modify all my textures magically huhu.

Seriously , you see what I mean ? I'm french , and my english is a bit rusty ...

If someone could help , 'd'be great Thanx a lot !