Adding in proposed bloodlines for the other three Clans.
Mekhet
Iktomi (Kokyangwuti): Minions of the Hopi Spider Grandmother, the Shadows that prowled California before its borders were drawn still watch over its people, aid those that deserve it and terrorizing the evil among them. Auspex, Celerity, Nightmare, Obfuscate. (Custom.) (Think Vampire Sluagh, with a leaning towards the Lynx.)
Iltana (Ishhara): These Shadows claim descent from Queen Iltani, an ancient ruler in Babylon, who mastered and managed her husband’s household with ruthless efficiency, and was supposedly sent by the Scorpion Queen herself. Animalism, Auspex, Celerity, Obfuscate. (AB, p. 145.) (Scorpion wins. Also, Merges Sorcery)
Otaku (Hotei): Some Shadows don’t like to stay there; some of them enjoy being in the spotlight, or, in the case of the Japanese Otaku, becoming the culture that they have watched from afar. Auspex, Celerity, Majesty, Obfuscate. (BL:Legendary, p. 117.) (The Players, but with a sinister, macabre, Japanese anime twist, with Devotions similar to The Moulding Room.)
Nosferatu
Cauldron-Born (Arawn): Allegedly spawned from a magic cauldron, these Haunts are the undead servants of Matholwch, an ancient Irish King who fought against the giants of Britain before the coming of Rome, who have mastered the power of death, which they use to rule their underground fiefdoms. Dominate, Nightmare, Obfuscate, Vigor. (BL:Legendary, p. 10.) (The non-Lancea Sanctum side of the Bron, and more in line with what the Mabinogion described.)
Stone-Clad (Atahsaia): The quixotic Stone-Clads prefer the sanctity of the mountains and open spaces than the concrete of cities, but their patron demon of Zuni mythology has other ideas for the foreigners that have spoiled the land. Nightmare, Obfuscate, Resilience, Vigor. (Custom.) (Stoneskinned cannibals (you may recall the same as nunnehi), I sort of see these guys as being bruisers that would rather spend their evenings staring up at the sky)
Rakshasa (Mahishasura): The divine opposites of the Shakti, these monstrous Haunts claim lineage from a great buffalo demon, and seek enlightenment in battle to become true demons. Nightmare, Obfuscate, Protean, Vigor. (BL:Hidden, p. 116.) (The opposite of the Shakti, who feast on the fear of their enemies.)
Ventrue
Dayyani (Tiamat): Whereas the Kerberoi claim that they were the first arbiters as to who should be embraced, the Dayyani claim that they were the first judges in the first cities of Mesopotamia. They believe their authority was usurped by the male priests of the Storm-God Marduk. Now, they seek a reversal of fortunes for patriarchal society. Animalism, Dominate, Nightmare, Resilience. (Custom.) (Sort of a new idea, intended to play off with the Iltani; probably have some ancient sort of magic, but I'm not sure what yet, if any.)
Kupua (Maui): What can I say except “you’re welcome”? These Polynesian seafarers are known for playing pranks on others, some of which have had deadly consequences. Animalism, Dominate, Protean, Resilience. (Custom.) (Because Sharkhead, that's why. Also, plays into West Coast surfer culture -- basically, Polynesian Rotgrafen)
Nahualli (Huitzilopochtli): A relatively-new bloodline, the Nahaulli derive their beliefs from Aztec philosophies, and more often than not give their sacrifices to the Aztec God of War. Animalism, Auspex, Dominate, Resilience. (BL:Hidden, p. 78.) (As per the Bloodline book.)
That's what I've come up with so far. I haven't written anything out in detail. ZG, if you want me to work on these, I can, but it might take a few weeks; that batch I did for The Descent took my three or four weeks of constant work, and my RL work and life schedule is pretty hectic.