I have always wanted to get a Sleipnir as a mount, but unless you are playing a high level campaign from the start, it takes a very long time if you start from level one and work your way to where you can get one using regular pathfinder rules. I think the only viable way to get one would be to have the leadership feat and have a pc level of 18 in order to qualify to recruit one as a monstrous cohort.
So enter the idea of the demisleipnir. Using a combination of the animal companion/mount class feature, monstrous mount and monstrous mount mastery mastery, and an animal companion archetype specifically for it to spice things up.
Demisleipnir
Like their demigod counterparts, demisleipnirs are a product of a mating between a slepnir and a regular horse, although even the horse must be of extraordinary quality and impeccable breed to catch the eye of the legendary mounts of the gods. They are often slightly bigger than regular horses and share some the extraordinary qualities of their legendary sire/dams. They have six legs, 4 in front and two in back. Are known for their endurance and power. While not quite as powerful as their sleipnir brethren, they are far easier to tame and train. This makes them highly prized and sought after as mounts and animal companions, unfortunately they are even rarer and harder to find than an actual sleipnir.
Monstrous Mount stat block:
Demisleipnir
Prerequisite(s): Diplomacy or Intimidate 5 ranks; Ride 5 ranks; languages Auran.
Starting Statistics
Size Large; Speed 50 ft.; AC +4 natural armor; Attack bite (1d4), 2 hooves (1d6); Ability Scores Str 18, Dex 13, Con 17, Int 6, Wis 12, Cha 10; Languages Auran (cannot speak); Special Qualities darkvision 60 ft., low-light vision.
7th-Level Advancement
Attack bite (1d4), 4 hooves (1d6); Special Attacks powerful charge (hooves, 2d8+(2 *Str mod), trample (slam, 1d8+(1.5*Str mod))
Mastery (7th Level)
Constant—air walk (CL = number of HD-4, and concentration = CL + Charisma modifier)
Blood of the Gods (demisleipnir companion archetype)
Some demisleipnirs take more after their noble kin and can display and use abilites and powers others of their kind do not have due to their diluted bloodline.
Crushing Hooves(Ex)
The demisleipnir companion gains multi-attack as a bonus feat
This replaces share spells
Godly Resistance(Ex)
At 3rd level, the demisleipnir companion gains electricity resistance 5.
This replaces evasion
Imporved Godly Resistance(Ex)
At 6th level, the demisleipnir companion's electricity resistance increases to 10 and it gains cold resistance 5. At 15th level, it becomes immune to electricity and its cold resistance increases to 10.
This replaces devotion
Breath Weapon(Su)
At 9th level, the demisleipnir companion gains a breath weapon, usable once per day. As a standard action, a demisleipnir can exhale a 30-foot cone of shimmering, rainbow-colored light. Every creature in the area is randomly struck by one or more beams, as a prismatic spray spell (DC = 10 + half the demisleipnir companion’s Hit Dice + the demisleipnir companion’s Constitution modifier half or negates.) At 15th level it can use the breath weapon twice a day, but it must wait 1d6 rounds between uses.
This replaces Multiattack(one gained from animal companion table) and improved evasion.
This what I have come up with so far, I tried to make something powerful and balanced, but not game breaking. Tell me what you guys think of it, any input or suggestions is gladly welcomed and appreciated.