I'm confused how would a mane roll not show off a long mane? All it is, is a ribbon or fabric braided into the very top of the mane, the rest of the mane hangs lose? We did it for haflinger's with a mane to their chest, looked good if you put draft darts in it. We only did the french braid because the heavy mane's got caught up in the reins making it annoying for the header to have to hop off and fix it every five minutes.
What do you consider a normal draft mane? I've never seen one cut or pulled before, long is normal nothing new about that, either that or hogged. But the show Clydesdale have longer and thicker mane's than the ones you posted.