Race Concept: Incorporeal?

[Voldrath]

You said they were trapped between planes so they probably wouldn't be truly ethereal. Perhaps you could give them some sort of psuedo-corporeality.
something like normal weapons have a 50% miss and effects than can strike ethereal only miss 25%. Couple thet with a CON penalty and some sort of limmit on how they move through objects (maby by densety) and it wouldn't be too far off.

 

[Izerath]

Incorporeal races

Have you thought about checking out Ghostwalk? It has some very good rules about handling incorporeal creatures without worrying about whether they have this ability score or not. Used in combination with the racial paragon concept, I would think you could craft an incorporeal CP race fairly easily.

 

[evolved]

according to savage species incorporeal is worth a +2 level adjustment.
if the race is naturally incorporeal then a stength or con penalty may be appropriate given that the only creatures that could normally harm them would be other incorporeals who tend to be weak in those areas as well, if they are incorporeal because of planar influesnce then anything goes because their are some buff monsters in the ethereal and astral planes (gith'yanki Gish ugh!) also consider the availiability of ghost touch weapons, abilities, and armor a good way to reduce the power of incorporeals is to make ghost touch a +1 ability for armor and shields instead of +3 (thats used in the ghostwalk campaign) or to make most important buildings with gorgon blood in the mortar to prevent ethereal travel, the spirits of past rulers or owners haunt the passage from the shadow plane, and there are Gish in the astral so if their incorporeality is drawn from one of the transitive planes there are some ideas to balance it also if a creature is incorporeal due to planar influences they are generally solid ofn that plane when they are incorporeal in the material and vise a versa

also who says a person couldn't make a trap with ghost touch arrows or drown an incorporeal foe in preserved gorgons blood