One more try...

[Curbstomp]

Personally I would avoid the DMM cheese. It's nice and all but kind of vulnerable to dispel.

Maybe something like this (This is assuming no flaws.):

Human
Duskblade 1 (Armored Mage: Light), Travel Devotion, Iron Will
Duskblade 2 (Combat Casting), Knowledge Devotion
Duskblade 3 (Arcane Channeling), Spell Focus: Evil
Duskblade 4 (Armored Mage: Medium)
Duskblade 5 (Quick cast 1/day)
Ur-priest 1 Arcane Strike
Ur-priest 2
Mystic Theurge 1
Mystic Theurge 2 Power Attack
Mystic Theurge 3
Mystic Theurge 4
Mystic Theurge 5 Cleave
Mystic Theurge 6
Mystic Theurge 7
Mystic Theurge 8 Great Cleave

Five levels are left to play with. You'll have 9th level spells by character level 14 or 15 depending on stats. I would suggest simply utilizing an Extend Rod if you really want longer-lasting spells. If flaws are allowed pick up Power Attack and Cleave earlier. My build is a mite stringent in that you need to be evil, but it does out-curve your build and suits the godless theme you seemed to be shooting for.