I'm running this sort of character myself. Here are some tips:
Backstab, backstab, and backstab. Then, if they're still alive, backstab again. Rogues have Lethality, which subs Cunning for Strength when calculating damage. Then, pick up the Assassin spec first. The reason for this is their Level 12 skill, Exploit Weakness. Basically, when you have Exploit Weakness, every backstab you do gets additional damage. The size of the boost is directly tied to your already massive Cunning score.
Don't bother with Strength. You can get equipment to boost your Strength up high enough to equip the good stuff. Make Wade's Drakescale Armor (the first version), then never talk to him about Drakescales again. The reason is that Wade's Emporium has an item called the Felon's Coat, which gives some amazing boosts that really help out a Rogue. Once you've purchased the Felon's Coat, you can start making Drakescale armor again.
Get Dexterity up to 24 as fast as possible (26 if you have the Edge). This, along with several accessories and equipment, will allow you to equip anything you need.
Rule 1: Momentum = god. Rule 2: See rule 1. Momentum is a sustained ability that requires 24 Dexterity, and it drastically increases your DPS by drasically increasing your attack rate. You probably won't want to get it right off the bat, as it restricts your options at a time when you have very few options, but later on, it's an excellent skill, and I personally plan to keep it on at all times.
Riposte and Dirty Fighting combined with Coup de Grace are amazing. Stun them, then you can backstab them while standing in front of them while they're stunned. Riposte is a little more costly early on, especially when combined with Momentum, but a stun+crit move is going to soften them up for you.
Don't bother with Dual Weapon Expert. I've never seen a Backstab crit, because Backstab damage = Crit damage. Also, the damage from bleeding can be outdone with a couple of backstabs. Get the first two abilities in the chain, but ignore the rest.
Learn to manage threat. Let your tank build it up, then turn around and backstab the enemy to death for being so stupid as to turn their back on you. If an enemy turns to you, stun them and backstab them some more.
Stealth is very nice, but it's very hard to fit in with everything else that makes a Rogue amazing. I work just fine without it.
Your Cunnning skill is too low. Even if you've never seen a Cunning score that high, it's still too low.
Final armor set for maximizing DPS looks something like this, according to Discobird:
Main Hand: The Rose's Thorn
Off-Hand: Thorn of the Dead Gods (Silverite) or The Edge
Helm: Helm of Honnleath
Body: Felon Coat
Golves: Red Jenny Seekers
Feet: Either the Cadash Stompers or the Silverhammer's Taskmasters (Stompers increase hostility, but are otherwise amazing)
Amulet: Whatever the hell you want. I plan on the Blood Gorged Amulet, myself.
Belt: Andruil's Blessing
Ring 1: Key to the City
Ring 2: Harvest Festival Ring
I realize I'm jumping all over the place, but I've been awake for about 16 hours now, and my brain is kinda screwy at the moment. The advice is pretty sound, even if the order is all sorts of screwy.
Oh, and as you probably guessed, Human Noble has better stats for a Rogue than the other races do.