I thought it sounded cool.

Anyway, in a burst of creativity (stemming from refusal to believe scorpion wire is not the amazing skill I believe it to be), I was going through the components that make a great (spike) sin build:
Damage
Synergy (the spike executes well)
Speed (try to keep as few dagger attacks as possible)
And everyone knows the best way to get all these three in one is cut back as much as possible on lead attacks: more dual attacks. Dual attacks do big damage, and the # of these basically determine a dagger sins spiking capability. Now of course the only reasonable way to get two dual attacks in a bar without having 6/8 dagger skills is cutting back on lead attacks. Hence the favored dagger skills are off-hand attacks that require no lead, these being:
Black Spider Strike
Golden Phoenix Strike
Falling Lotus
Falling Spider
The elimination of Black Lotus Strike basically elimanted dual offhand-dual dual attack sin bars, as Enchantment/Hex combo hogs too much skill bar room, and allows for no KD's. Lotus/Spider Is simply implausible because KD is too hard a condition to fulfill twice.
Lotus/Spider + Phoenix/BlackSpider is the only plausible option, but even these possible combination do not work as well as simply using lead attacks (the only synergistic kd's are dagger dual attacks, one of which sucks -HOTO- and the other of which's condition is simply cannot be fulfilled in a 4 dagger chain. Non-1/4sec hexes are a major giveaway for a spike, while instability is simply has no value other than the KD, you might as well take a lead attack in its place.
Hence, my insane creation!
[build prof=Assassin/Elementalist][Scorpion Wire][Falling Lotus Strike][Twisting Fangs][Golden Phoenix Strike][Blades of Steel][Conjure Lightning][Shadow Meld][No Skill][/build]
The build is mainly ment to rape in AB. It CAN work to some extent in HB (though 100' is 1 bubble and 1/4, so its not synergistic with high lvl HB as you must leave capping range to spike). It can work in GvG effectively, and RA/TA with relative effectiveness (maps tend to be small)
My favorite aspect of the build is that it encourages SKILLFUL ASSASSIN PLAY - Holy sh*t, right?
This is simply so because the usage and build can be extremely effective if used smart, aswell as executing the spike requires more than 1-2-3-4.
The idea is to cast shadow meld on an ally as soon as you get in, find a target, close within range for scorpion wire, release shadow meld, teleporting you more than 100' away (if you placed your meld smart), thus activating scorpion wire in a matter of 1/2 of a second, from here simply execute your chain.
But thats not it! When you click on shadow meld to release it, you auto-target yourself. So? So basically, if auto targeting is on, when you teleport to your victim auto target will target the enemy closest to you and closest to the center of the screen - because you can teleport anywhere in a 360 degree angle around your victim, its pretty impossible to position your screen perfect, often finding yourself trying to execute a lotus on a completely different target.
The way to get it to go smoothly is simple - bind the "priority target" targeting key somewhere reachable on your keyboard, or as close to your lotus key as possible. When you find a victim, ctrl + attack to call them as a target, now pressing that key you binded will automatically target them. After you release meld, simply mash on that key along with lotus strike. Mashing isnt really guaranteed, but thats how most will do it - guarenteed is to wait until you see wire activating, and then hit your priority target key a few times, followed by lotus. The key here is targeting first, then lotus, same time = bad. Now in ab or something of the sort one of your party members might call I priority target, overtop your own target, you can usually re-call right over theres again, but your safest bet is to just press the little symbol next to your name on the party menu, this will guarentee you find the right target.
As for the build its something like:
11 Dagger + 1 + 1
11 or 12 in Air (whatever adds +17 per hit)
rest in Crit + 1
Spike Energy - About 20, leaving you to be free to use survivors/vitae
Spike DPS - Shouldve taken it to the master of dmg, can take down the 100al with great ease
Optionals/Varients:
[skill]Aura of Displacement[/skill] can replace meld, though I have not tested it I doubt it would be any different in targetting, but if you want to have a range for your wire every time your best bet is meld.
You can go /W for a IAS, or any other secondary you fancy as long as you have a enchantment (shadow refuge can even work, just cast before the spike) for golden pheonix.