Why not try for dragon instead of outsider, you don't have to worry about low level resurection spells not working(probably not a big deal if its a BBEG), you get d12 HD instead of d8, immunity to paralysis and sleep effects, and low light vision(not sure if this really matters much). In exchange you would lose 2 skill a level, the not needing of food and sleep, and proficiency with martial weapons(from the outsider type).
Depending on what you want to do Dragon may be the better option, how to get the dragon type is a bit harder than the outsider type but may the better of the two to pick. The only way I can think to pull this off is half drag, but that has 3 LA, Incarnate construct would lower that to +1, but I think that would make you lose the subtype then.