You're calling 5 natural armor negligible? That's like worth +1 LA all on its own (consider lizardfolk).
Anyway, from what you're saying the sharn's raw melee stats must look something like this -- Sharn: CR ?; AC 19; hp 38; Spd 10, fly 40; Face/Reach 10/10; Atk 3 claws +6 (1d6+4), 6 claws +4 (1d6+2), 3 bites +4 (2d6+2); SA quickness; SQ DR 10/cold iron, regenerate 2, etc.
The natural armor plus DR plus regeneration stacks up for a considerable defense. Running this through my melee simulator program, even as just a brute melee fighter the Sharn can hold its own against up to a 10th-level NPC fighter (assuming no cold iron or Lawful weapon). That indicates a baseline of +6 LA right there, without considering flight or any other abilities.
I'd ballpark another +3 on top of that for (1) flight, (2) the good mental stats, and (3) miscellaneous immunities, evasion, and "hex portals".
So my guess is LA +9. The base creature would have a total ECL of 13.
EDIT: However, by virtue of some online clues, I might guess that there are still other significant powers that haven't been addressed yet.