Ok, sounds feasible. I think I can create a 'Following' of a chosen deity and go from there. As fro the routing out of evil, I think I can manage to simply find some way of deeming our main foes as corruptors of his faith in some way.
Here goes:
Option 1
1) Chose a character alignment - Choatic Good
2) Chose a deity - Zinnastine
3) Decide what your alignment says about your deities aspect. - Weather the storms, for they will judge the worthy. The unworthy will feel the wrath of the gods while the worthy will find nature's blessing.
4) What domains fit - Air, Healing, Plant, Sun, Water, Weather
5) Pick a weapon that fits - Trident (Seriously, how often do you see a Trident being used? Longspear or Spear would work as well, considering he would be using Storms, which would eventually call down lightning)
6) Name this new church/cult - The Tempests Order
7) Domain would be Weather - Gain Storm Burst and at 8th level gain Lightning Lord (Both offensive ranged attacks dealing with bringing down the wrath of the gods onto foes)
Option 2
1) Chose a character alignment - Neutral Good
2) Chose a deity - Gracenys
3) Decide what your alignment says about your deities aspect. - Leadership is worthless without those who follow. Teach, so that you may learn. Learn, so that you may teach others.
4) What domains fit - Community, Glory, Good, Knowledge, Nobility, Protection, Strength
5) Pick a weapon that fits - Longsword? ( No idea really on this one... )
6) Name this new church/cult - The Guiding Hand
7) Domain would be Nobility: Grants Inspiring Word, and at 8th level gain Leadership with +2 bonus to Leadership Score (Not sure if Leadership would be a feat worth taking in this type of campaign, but can't hurt with asking)
At least I have it narrowed down to only 2 Domains now...