...about the commonality of Viking weapons and armor, indeed, the shield was about all the average Viking could afford.

Coats of mail (especially the "treble-plated coats of mail" worn by the Vikings at Clontarf, mentioned in the Annals of Ulster...further proof that sagas, et al are not always entirely accurate) were the providence of Kings, Jarls, and certain privileged thanes. It was difficult to make (trust me, I make chainmail - done in period method, it takes MONTHS), costly, and not to mention REALLY FREAKIN' HEAVY*. A coat of mail, single woven, weighs about 40 pounds or so. Most of that weight falls on your shoulders. If you were on a longship and happened to drop over the side (which was not uncommon), you would hit the ocean floor like a bloody dart. So, consequently, most vikings didn't bother with armor.

*this may not seem real heavy, but try wearing it while doing the equivalent of an aerobic workout for about three or four hours. THEN you tell me it's "not that heavy".