With that in mind, here we go...
Using the idea that Sin primary stat resembles a Ranger's Primary stat [indeed, to me, a sin is like a melee ranger...

Here's the idea:
A/N [could be /X to you guys]
13 Critical Strikes
16 Dagger Mastery [with +3 crit rune, so cheap to get ^_^]
4 Shadow Arts, er whatever... [all runed up, etc.]
Black Lotus Strike
Twisting Fangs
Falling Spider
Critical Strike
Mark of Instability
Aura of Displacement {E} [also for +15% enchant based daggers]
Plague Touch
Res Signet
As you can see, the brunt of this build is about landing a very high ranking 13 Critical skill bunch of attacks in full succession. To be used after a fight is well under way and the sin has chosen victim to snipe... AoD {E} fits well with the recycle time of BLS. After my runs with a sin, sins do NOT attack until after everyone has engaged a mob and AFTER it's safe to blaze in without fear of getting beat down... Your experience maybe different from mine but I see sins as 'snipers' in a way...
Idea is straightforward so long as enemy is occupied and doesn't remove Mark of Instability. Cast it first, then AoD in...
Let lose with BLS into Twisting Fangs, now they're Bleeding, Deep Wounded, and on their ass. Falling Spider and Critical Strike allows you to regen a hefty amount of energy and then you can cancel AoD and wait for your handiwork to kill...
I was thinking of using Death Blossom for the final strike instead of Critical Strike but I'm not sure if blasting a mob with a sin is a good idea... [ya know, sin's don't tank, in my method of gaming anyway]
Ideas? PvE methods to killing faster than this build? If there's a way to do more damage to one foe and still have energy to spare, [or no energy if a combo is that intensive], I'm all eyes and ears...
Thanks for the help! ^_^
p.s. would switching the stats: 13 dagger/16 critical be a better idea since you'd not only get more crit, but there are more crit strike skills in there than dagger mastery and I'm not sure if the dmg bonuses for the two work well in either case. As a warrior favorite, I'd think 16 dagger, 13 critical is better, but with 3 of the strikes in Critical stat, I'm questioning it's effectiveness...