Loosely based off the Shadowswyft. I will add more as I go along...
Moonswyft have the following racial abilities and characteristics.
• +4 Dexterity, -2 Strength, -2 Constitution. Moonswyfts are deft, but are frail and not very strong physically.
• Outsider: Moonswyfts are native to the Astral Plane, and thus have the outsider type. They gain the extraplanar subtype when not on the Astral Plane. They are not affected by spells or effects that effect only humanoids.
• Medium: As medium creatures, Moonswyfts have no special bonuses or penalties due to their size.
• A Moonswyft's base land speed is 40 feet, and may traverse at 40 feet on any and all terrain, except for pure void. Air does not count as a terrain, but this ability does grant the ability to traverse water, and climb vertical terrain effortlessly. This ability does not grant flight, or in any way allow the Moonswyft to fly.
• Low-Light Vision (Four times as good as a Human)
• Skills: Moonswyfts have a +2 bonus to Hide, Move Silently and Tumble Checks.
• Turn Ethereal (Su). Once per day as a free action, a Moonswyft may enter the Ethereal Plane for 10 minutes. Doing so will tire the Moonswyft and he will be fatigued until the end of the day. If the Moonswyft is already fatigued, he will instead become exhausted, and take 10 points of nonlethal damage.
• Automatic Languages: Common, Shadowswyft. Bonus Languages: Abyssal, Infernal, Celestial, Draconic.
• Favored Class:
• Level Adjustment +2
Anyway, I have a few more ideas to throw out there, but what do you guys think so far...?