Natural armor bonus? The similarly CRed sea linnorm has +36, which is actually superior to that of the higher-CRed dread (+30) and corpse tearer (+28) linnorms.
Suggested damage reduction?
Sea linnorm has 30/magic, dread 15/magic, and corpse tearer 20/magic. The swamp linnorm has 10/cold iron. I'd actually prefer the cold iron, or maybe 10/epic.
The MM2 linnorms are really paragon examples of terrible high-level game design. There's a reason I completely scrapped and redid their stats when I was converting stuff out of the MM2.
Skills: 8 at 29 ranks
Standard linnorm skills:
Bluff, Concentration, Diplomacy, Intimidate, Knowledge (arcana), Listen, Search, Sense Motive, Spellcraft, Spot, Swim
Feats: Multiattack, 8 more (2 can be epic)
Standard linnorm feats:
Alertness, Flyby Attack, Multiattack, Snatch
Other feats: Ability Focus, Cleave, Power Attack, metamagic feats
That'll give us Cleave, Devasting Critical (bite), Great Cleave, Improved Critical (bite), Overwhelming Critical (bite), Power Attack, Weapon Focus (bite). That leaves one more feat (which cannot be epic). How about Snatch?