Thanks for the suggestions and the link. Both are very interesting. I like the idea of increasing the difficulty as the character advances through the good/evil axis.
My group aren't 'heavy' on the role-playing side of things but also not solely fixed killing and grabbing loot either. Somewhere in the middle. This means the perks need to more tangible.
How does this sound?
Good +1: Choice of +4 to stabilizing checks or +2 Heal skill check
Good +2: Smite evil as level Paladin of half level 1/day or +1 smite if already a Paladin.
Good +3: May use Holy Smite 1/day
Good +4: May use Angelic Aspect 1/day
Good +5: Gains a Guardian Angel of sorts. 1/day may summon a specific good outsider to assist in a task or battle.
These perks would be cumulative. Also, I was thinking that from good +3 onwards, the character would have a good aura detectable by certain creatures or spells.
Obviously a first draft and quite rough. I probably need to split the perks into a different lists depending on the character. i.e. melee combat, spell caster or something else if the character is more of a helping the weak and innocent type and less of a crusader! It's hard to imagine the aged and frail village healer suddenly sprouting wings and smiting the local thugs!