Handee is right in that those can be (depending on their random stats) the best one handed swords in the game, and you're right in that they can be available only after stormfist castle.
I can't think of any other unique one-handed swords - however Geoff (the blacksmith in Ars) always sold a variety, and some of the randomly generated "named" swords, while only having dmg up to 65, had wonderful extras as frost, mana drain, death blow, etc and thus were partially extremely powerful. So if you are inclined visit him and reload repetitively, and see what luck generates.
