For general template stacking guidelines, go with Savage Species & the appendices in the various Monster Manuals.
In addition to what Psion said (in case that isn't enough), each creature's respective Environments are diametrically opposed. I don't think there are any official planes out there that have both good- & evil- alignment traits. Plus the flavor text states that each type dwells on upper or lower planes, respectively. Hard to combine the two, outside of artificial manipulation (magical experimentation, rituals, etc.).