I've only ever heard of two horned helmets being found, both at a burial site in Denmark. As I understood, they portrayed themselves in art as having horns to intimidate the enemy, same thing for double-bladed battle axes.
Regardless, I feel the game goes to far out of it's way to say "Look, we're stereotypical vikings!" when it should be saying "Look, we're Nords!". Not that the two don't bare many similarities, but I feel like Beth should have done something to really set them apart. Like Snow Whales. Really, its an aesthetic issue. I'm not interested in exploring Skyrim because, aside from Blackreach, I just keep thinking "I've seen this all before" because everything feels distinctly Scandinavian. One simple fix for this would be the adding of larger and more abnormal creatures, at the most in the vanilla game real world animals just have a few extra tusks. I mean, it is a step up from Oblivion, but still. The Nords are supposed to be Scandinavian influenced, not Scandinavian.
Again, burial rituals, entire religion, architecture, all different. Really aside from just "feeling" Viking-ish, there is not too much I can actually point to and say "this is a Viking thing." Iron Sword definitely looks like a viking sword. But the religion seems a smash-together of Norse and Hindu with a few dashes of Druidic ritual and, with the greybeards, some new stuff. Huge Egyptian influence in their shown burial traditions, with complex embalming and mummification rituals.
As for images of Shor, in his serpent-form I imagine him to be a green Volvagia with no forepaws and long, whiplike scales instead of flames for his mane. This then fights Alduin and it looks awesome in my head but I can't draw so too bad.