A little tidbit:
Ulfberht (spelling varies) was a well known and prestigious swordmaker of the time. I've read that it is a curiously over-represented "brand name" on a good many surviving swords. There is some speculation that not all swords bearing the Ulfberht mark were actually "genuine". Their reputation made them very expensive. Trademark enforcement would have been difficult and it is thought that some smiths (or more likely dealers) may have counterfeited the mark to increase the sales value of their swords.
Of course it is also logical that more expensive equipment is more likely to be preserved through many generations and thus they would naturally be over-represented in surviving collections than others. I don't know if we'll ever know things like that for sure.
Sword ping list.