Excellent looking Normans Cheng!
The Norman period is very close to my favorite period in the Middle Ages, so the arms and armor are not substantially different. I try to keep my knights from a slightly earlier period than the produced sets now-a-days, but some of my figures will have plate.
The problem with making a completely Norman army is that too many sets come with plate armor now. It would be pretty hard to find good figures for Normans without there being some plate. The earlier Playmobil Knight sets were pretty good, in that you could probably make very nice Norman figures quite easily.