Race:
Dunmer, 7% flame dmg + 9% magicka

* I made my dragonknight a vampire, because the 10% recovery from stage 2 is highly appreciated.

Mundus:
TBS = Thief + Shadow
if you're wearing Law of Julianos, use the Thief mundus

Gear:
2x Grothdarr
5x Twise Born Star or Julianos
3x Moondancer or Inf. Aether (with spelldmg enchants)
1x Maelstrom Firestaff Sharpend (1st bar)
1x Moondancer or Inf. Aether Firestaff (4piece bonus + spelldmg enchant) (2nd bar)
* You can use Law of Julianos instead of TBS. With multiple warhorns, TBS will always be better.

Skills:
Since most groups expect certain utility and crowd control from a magicka dragonknight in raid setups. You'll need to replace ''Rearming Trap'' for ''Unrelenting Grip''. ''Elemental ring'' is also exchangeable with ''Burning Talons'' if a root is needed.
Use ''Forcepulse'' for range encounters.
Slot ''innerlight'' on both bars for pure singletarget fights. (max magicka bug a.t.m.)

Cheap setup:
Use Molten/Igneous weapons to save spellpower potions.