Needs moar Hellbreaker from Fiendish Codex II. Full BAB melee class with swift action boosts that include healing, smiting, and general merriment. You also get the ability to smack a fool so hard, he forgets how to teleport. Great entry includes Spirit Lion Barb1/Pal of Freedom4/Hellbreaker10. Gets Turn Undead for Divine/Devotion feats, pounce, full BAB for maximum PA conversion, etc.
Good in general for melee, GREAT for Fiendslaying specifically.
EDIT: Pal of Freedom gives you immunity to Charm/Compulsions and Hellbreaker covers [Fear]. Between them, you have 95% of the benefits of Mind Blank at ECL 6. Not half bad.