Ok, at the idea from `Insolence`, I have finally semi-completed a Poison Necro for Pit Runs. The thing is, this guy kicks some serious ass. My average time for clearing the ENTIRE Pit is ~3:00. That includes teleporting there and identifying a few items. This is a guide as to what you would want to look at. Here goes:
Stat Points
STR Enough for your armor.
DEX Keep your block % up, ~50% or higher is good.
VIT Leftover points go here
ENE Base
Skill Points
20 Poison Dagger
20 Poison Explosion
20 Poison Nova
20 Bone Wall
1 Bone Armor
1 Teeth
1 Corpse Explosion
1 Amplify Damage
1 Iron Maiden
1 Life Tap
1 Weaken
1 Terror
1 Decrepify
1-5 Lower Resist
That is 90-94 skill points in total, so this build would be complete at prior to level 78-82 using all skill quests.
Equipment
Helm: +2 Necro/20% FCR/+All Resists Circlet (Harlequin Crest will likely be what people use)
Armor: 'Enigma'/'Bramble' (Enigma preferably, as teleporting speeds up runs)
Weapon: Death's Web/'Heart of the Oak' (Blackbog's Sharp if you're pretty poor)
Shield: Trang Oul's Wing
Gloves: Trang Oul's Claw
Belt: Trang Oul's Girth
Boots: Marrowwalk
Rings: 2x Stone of Jordan
Amulet: Storm Circlet or other rare/crafted ammy (Mara's would work too)
I know most people will ask "Why Trang Oul's Shield and Belt instead of Homonculus + Arachnid's Mesh?". The reason is, that with the 3 set pieces, the shield will give -25% Enemy Poison Resistance. That is a HUGE help vs. the skeletons in the Pit, as they are a bit resistant to poison.
If you have any gear you could socket, try to procure some Poison Rainbow Facets. Those would help immensely.
Of course, a few +1 Poison and Bone charms would help this build, so if you have some, don't be afraid to use them.
That's pretty much about it. Feel free to post questions/comments in here.