I think what you're looking for isn't so much found in a particular weapon skill line, but rather the Ardent Flame skill line for the Dragon Knight. This is a combination of melee and fire spells, although more centered around 2H weapons. Not sure if this answers your question much, but it's the closest thing to a "spellsword" build that I can think of.

My main character is an Sorcerer with Storm Calling using Duel Wield. I use the Duel Wield as main dmg even tho i use 3 Storm Calling abilitys in my bar and 2 Duel Wield. But that works really good for me.
But if you wanted an casting Sorcerer i know one who uses Heavy Armor & Two-handed Weapon and mainly using casting abillitys, thats working really good aswell.

Hope this helps you