I have Falseiron, a 18/2 Wiz/Fighter that works wonders. I get Level 9 spells (Power Word Kill, Wail of the Banshee, and Meteor Swarm), and some basics from Fighter. He is Warforged (Mithril docent), thus has access to that enhancement line to reduce spell failure (-15% I believe. It's enough to have no fails by around level 9). Instead of sword/board, he TWFs with khopeshes. Not tank-edy damage, but I can still melee Trogs and even some Bearded Devils in Shroud consistently.
If you want the trap ability, consider 18/1/1 of Wizard/Artificer/Fighter. Rogue also would work instead of Artificer. You might not have full trap ability at high-end, but you get Tier 3 PM (or Archmage V, if you go that route), all spell levels, and enough instakills to clear out a gnoll village.
As is, looks like you have a pretty solid build, and I would love to see the Tarcane in battle!