If it were me making this, I'd cut eight pieces of heavy flat stock like the sections of the pictured flail head. I'd do some forging to stylize them a bit like the example piece, then [mig] weld them to a central round rod. I'd probably find some old chain, heat it up in the fire once and put some oil/wax on it when it's cooling down (just to keep everything looking like it belongs together). Then I'd probably make the handle fittings by brazing flutes to central collars. I think the trick is in making it look good with fit and finish.