Well, that result it's probably perfected with a tablet. I try to do the same (with nice but not so effective results) using both the sketch render and the lightworks one, made separately and finally combined using phothoshop, adding some effects... look at my example...
I'm waiting for the new cintiq, to improve the quality of a sketched render. But I really think that archicad will never be able to make a good render itself (lightworks doesn't have the radiosity and displacement, and the render engine is really old...): you could try with the maxwell render engine (but it requires a great computer) or try artlantis (easy to use but not very good) or, best of all, try Cinema 4D...
CIAO!
