H....hold on. Are we talking
Far Realm outsiders? Then I have the absolutely perfect thing for you! I created a fairly elaborate system, including a number of monsters and a new template, based on a race of sanity-draining creatures that initially came from the video game Eternal Darkness. And the monsters from said game were inspired, a lot, by the Cthulu mythos, which I always thought was just perfect Far Realm inspiration. Now, the highest-level monster that I made is only in teens, CR-wise, but then, that's what the template and advancement rules are for, right? The only question is do you want it now, or after this weekend, after I finished doing a 3.5 and difficulty adjust? I should have the other outsiders I mentioned (including two that would make nice Far Realm villains) by tonight, but it will probably take a bit longer than that to fix up the Eternal Darkness monsters. As a peace offering for making you wait, though, here's a nice near-epic monster for you to take a look at. It's more the "big, strong, and stupid" type than the "creepy outsider" type, but again, that's what template and advancment rules are for.

This guy was, incidentally, the monster that swallowed the monk and trampled the prismatic sphere in the story I mentioned in your regular story hour.
Murdean, Instant
Colossal Magical Beast
Hit Dice: 40d10+406 (626 hp)
Initiative: +10 (+6 Dex, +4 Improved Init)
Speed: 90 ft.
AC: 35 (-8 size, +6 Dex, +27 Natural)
Base Attack/Grapple: +40/56
Attack: Bite +46 melee (4d8 +14)
Full Attack: Bite +46 melee (4d8 + 14,) 2 Gore +41 melee (1d8 + 7,) 2 Claws +41 melee (1d8+ 7,) hooves +41 melee (2d8 +7)
Space/Reach: 30 feet/20 feet
SA: Frightful Presence, Trample, Buck, Improved Grab, Swallow Whole, Energy Transfer
SQ: DR 15/magic, immunity to fire, poison, energy drain, and ability damage, resistance to electricity, acid, and sonic 20, Stubborn Will, fast healing 15, SR 30
Saves: Fort +34, Ref +30, Will +17
Abilities: Str 38, Dex 22, Con 30
Int 3, Wis 14, Cha 14
Skills: Listen +15, Spot +15, Wilderness Lore +13, Search +7
Feats: Alertness, Blind-Fight, Cleave, Great Cleave, Combat Reflexes, Power Attack, Dodge, Improved Grapple, Improved Initiative, Iron Will, Great Fortitude, Lightning Reflexes, Toughness (2)
Climate/Terrain: Any land or underground
Organization: Solitary
Challenge Rating: 19
Treasure: None.
Alignment: Always chaotic neutral
Advancement: 41+ (Colossal)
It could be heard before it was seen, but not by much. An impossibly tall creature, it bore down up you faster than any creature so large had any right to move. It vaguely resembled a centaur, if centaurs were fifty feet long and sounded like thunderclaps every time their hooves pummeled the ground. But instead of the an upper half that was even vaguely human, it resembled some sort of ancient lizard, with claws like swords and a head like a crocodile. A crown of horns greater than any deer or elk ever could dream of having sits atop its head, further showing what an anachronism of nature the beast is.
In an alternate dimension, Murdeans are the answer to the Tarrasque, though they are not unique beings and are slightly weaker. Still, with their nearly infinite power, they are more than capable of destroying entire armies without difficulty. The Instant is only one of five varieties. Known for its speed, it is weaker than some of the other types, but is still an extremely vicious adversary.
Combat:
Instant Murdeans prefer to trample, buck, or swallow some adversaries, before attacking the survivors. Once into combat directly, it prefers to strike one enemy with its bite and horns, and then use its hooves to cause further damage to lesser enemies.
Frightful Presence (Su): A murdean can inspire terror by charging or attacking. Affected creatures must succeed on a DC 32 check or become shaken, remaining in that condition as long as they remain withn 60 feet of the murdean. The save DC is Charisma-based.
Trample (Ex): As a full-round action, an Instant can move up to twice its speed and literally run over any opponents at least one size category smaller than itself. The creature merely has to move over the opponents in its path; any creature whose space is completely covered by the trampling creature’s space is subject to the trample attack. A trample attack does bludgeoning damage equal to 2d8+21. Trampled opponents can make attacks of opportunity, but at a –4 penalty. If they do not make attacks of opportunity, they can attempt a Reflex save for half damage. The DC is 44.
Buck (Ex): At the end of a charge action, instead of making a normal attack, the Instant can instead make a Buck attack against a target. This works like a Bull Rush that doesn’t provoke an attack of opportunity (Instant’s bonus is +30.) Unlike a normal Bull Rush, the Instant does not have to continue moving with the rush to move the target more than five feet. In addition, this attack does 1d6 points of damage for every ten feet the target flew backwards, and the target has risen to a height equal to a half his distance over the course of the buck. This may cause additional falling damage as well.
Improved Grab (Ex): To use this ability, the Instant must hit a Huge or smaller opponent with its bite attack. It can then attempt to start a grapple as a free action without provoking an attack of opportunity. If it wins the grapple check, it can establish a hold and can try to swallow the foe the following round.
Swallow Whole (Ex): The Instant can try to swallow a grabbed opponent by making a successful grapple check. Once inside, the opponent takes 2d8+8 points of crushing damage and 2d8+6 points of acid damage per round from the Instant’s digestive juices. A swallowed creature can cut its way out by doing 50 points of damage to the Instant’s digestive tract (AC 23.) Once the creature exits, muscular action closes the hole; another swallowed creature must cuts its own way out. The Instant’s gullet can hold 2 Huge, 8 Large, 32 Medium, 128 Small, or 512 Tiny or smaller creatures.
Energy Transfer (Su): Whether or not it actually damages the creature, all energy-based attacks that successfully hit the Instant is partially absorbed and temporarily made part of the creature’s powers. After such an attack, all the creature’s natural weapons do 1d6 points of damage of the appropriate energy type in the next round. If attacked by multiple energy weapons, these effects stack. For example, an Instant hit by two fireballs and one lightning bolt would do 2d6 fire and 1d6 electricity damage with all natural attacks in the next round.
Stubborn Will (Ex): Murdeans are notoriously hard to control. As a result, they have a +4 to all mind-affecting will saves, and Wild Empathy/Handle Animal checks are made at a –4 penalty.