I know that the Horse/Pegasus mounts may be over done at this point but having a Black Pegasus with dark blue wing tips and hair with stars and constellations for AST would be amazing!

I'm still holding out hope for a Magicked Carpet mount personally (which would be perfect for Dancer)... but I'll definitely take Pegasus Constellation any day XD.

Also

War: Giant Armored War Boar or Goat
Pld: Giant Armored
Drk: Dread Steed (Black cloudy War Horse)
Gnb: Magitek Dog

Whm: White Peacock
Sch: Lunar Moth
Ast: Constellation Pegasus or Shooting Star

Brd: Magpie
Mch: Magitek Hoverboard
Dnc: Magicked Carpet

Blm: Floating Ley Lines
Smn: Bahamut Wings
Rdm: A Black wing and a White Wing made of aether

Blu: Floating Limited Sign

Nin: Flame Toad
Sam: A Giant Snake
Mnk: Temple of the Fist Coeurl
Drg: Elder Wyvern