Yeah, assassim/rogue into warlock will get you there pretty fast. Assassins have some pretty nifty encounter powers and utilities that can turn you invisible even without using shadow walk to hide.
Here is a neat rogue build with plenty of trickery:
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edit: Here's my version of the rogue/assassin hybrid
Lele Human Assassin Rogue, level 11
Human, Rogue|Assassin, Shadow Assassin
Hybrid Assassin: Hybrid Assassin Will
Hybrid Talent: Rogue Tactics (Hybrid)
Rogue Tactics (Hybrid): Cunning Sneak (Hybrid)
Human Power Selection: Bonus At-Will Power
Background: Occupation - Criminal (+2 to Thievery)
FINAL ABILITY SCORES
Str 10, Con 19, Dex 21, Int 11, Wis 11, Cha 14.
STARTING ABILITY SCORES
Str 9, Con 16, Dex 16, Int 10, Wis 10, Cha 13.
AC: 26 Fort: 22 Reflex: 26 Will: 21
HP: 70 Surges: 10 Surge Value: 17
TRAINED SKILLS
Bluff +12, Stealth +15, Thievery +17, Perception +10, Intimidate +12, Athletics +10, Acrobatics +15
UNTRAINED SKILLS
Arcana +5, Diplomacy +7, Dungeoneering +5, Endurance +9, Heal +5, History +5, Insight +5, Nature +5, Religion +5, Streetwise +7
FEATS
Human: Cursed Shadow
Level 1: Student of Malediction
Level 2: Hybrid Talent
Level 4: Light Blade Expertise
Level 6: Roguish Killer
Level 8: Deadeye Slinger
Level 10: Two-Weapon Fighting
Level 11: Two-Weapon Opening
POWERS
Bonus At-Will Power: Piercing Strike
Hybrid at-will 1: Executioner's Noose
Hybrid at-will 1: Deft Strike
Hybrid encounter 1: Gloom Thief
Hybrid daily 1: Blinding Barrage
Hybrid utility 2: Fleeting Ghost
Hybrid encounter 3: Low Slash
Hybrid daily 5: Twilight Assassin
Hybrid utility 6: Slayer's Escape
Hybrid encounter 7: Shadow Jack
Hybrid daily 9: Into Harm's Way
Hybrid utility 10: Seeker of Shadow
ITEMS
Shadowblade, Feytouched Drowmesh +3, Orc's-Eye Amulet +2, Rhythm Blade Short sword +1, Gauntlets of Blood (heroic tier), Muleback Harness (heroic tier), Rebounding Sling +2, Mithrendain Steel Rapier +2