Off the top of my head, and with no real forethought (so it will probably not be balanced or even usable), I bring you: The Will of Divinity.
HD: 1d4
Reqs: Ability to cast three Universal spells, one of which must be Limited Wish. Knowledge: Any two, 12 ranks. Must have had peaceful contact with a deity, via any means.
Class Skills: Concentration, all Knowledges, Spellcraft.
2 + Int mod skills.
1: BAB 0 - Fort 0, Ref 0, Will 2: +1 level of existing arcane spellcasting class. The Scent.
2: BAB 1 - Fort 0, Ref 0, Will 3: +1 level of existing arcane spellcasting class. The Trace.
3: BAB 1 - Fort 1, Ref 1, Will 3: +1 level of existing arcane spellcasting class. The Sight.
4: BAB 2 - Fort 1, Ref 1, Will 4: +1 level of existing arcane spellcasting class. The Voice.
5: BAB 2 - Fort 1, Ref 1, Will 4: +1 level of existing arcane spellcasting class. The Will.
The Scent (ex) : The Will of Divinity is finely attuned to the weave of magic, and as a free action can determine any spell that has been cast in the last day/lv in this class. This ability also allows the Will to determine any spells that are currently being cast as if he had successfully rolled a Spellcraft check.
The Trace (su) : The Will of Divinity is able to manipulate trace energy in spells that have previously been cast. As a free action, he may use that energy to cast a duplicate of any spell that found by The Smell. This ability is usable 1/day per level in this class.
The Sight (ex) - The Will is able to see the weave, giving him the effects True Seeing at will. Anytime he is targeted by a gaze attack, he automatically succeeds on his saving throw.
The Voice (ex): Once per day, the Will may let out a word of power. This mimics any of the effects of Limited Wish, with no experience penalty or material requirement.
The Will: No longer suffers EXP penalties from casting spells.