Favored Class: The half-elf has no favored class and never suffers an XP penalty for multiclassing.
Thats how I would word it
I don't think its too powerful (and in most games, wont amount to more than Favored Class: Any) and it has a certain flair about it. I like it, don't think its easily abused though its certainly possible.
For instance if you don't have restrictions on Paladins and Monks either (many games don't) then mixing those classes along with a couple levels of rogue, cleric, and ranger is "possibly" abusable, mostly because the saves will be through the roof.
Rog 2/Mnk2/Pal 2/Clr 1/Rgr 2 (3.5)
9th level Character
BAB: +6/+1
[same as any other 9th level char with "medium" BAB]
HP: 6 (first level rogue) + 1d6 + 5d8 + 2d10 + (Con x 9)
[Assuming the d6 and d10s roughly cancel each other out, you have the equivalent of 9d8. Same as 9th level Ranger, Cleric, Monk, etc.]
Saves: +10/+8/+8 (plus Divine Grace)
[Many points higher than an equivalent level monk, who should have the best all-around saves]
Class Abilities: Sneak Attack +1d6, Evasion, Unarmed Strike (1d6), Stunning Attack, Flurry of Blows, Deflect Arrows, Detect evil at Will, Divine grace, Lay on Hands (Cha x 2), Divine health, Aura of Courage, Smite Evil 1/day (+Cha to hit/+2 damage), 2 Domain Abilities, Turn Undead (as a 2nd level cleric if you stack pal levels), Track, Favored Enemy +2, Combat Path Feat (Ranger), Animal Companion, Wild Empathy.
[Obviously a laundry list of special abilities. Between monk bonus feats, ranger combat paths, and cleric domains this character has 5 "bonus" feats, the same number as a 9th level fighter (although far less choice about what they are).]
Skill Points (first level as a Rogue): 64 + (Int x 12)
[This is slightly less than a 9th level Bard or Ranger (3.5), but more than anyone else besides a dedicated rogue. Granted, the class skills and determination of spending said points would be quite a pain.]
Spells: as a 1st level cleric
It would be good to keep in mind that this is more or less the most abusable level to look at this character. Hes done multiclassing into base classes, now hes looking towards prestige. He also has the "burden" of the paladin's code (and thus a strict LG alignment) and the monk's restriction on armor (which is balanced with the monk's Wis to AC bonus).
Of course, as I finish this I realize that said character is technically not breaking any existing multiclass rules...
Technik