I like the idea of the Conc Barb, and even moreso of following one person so a group doesn't get split up. One thing though, how many people actually know most all of the map patterns? I wouldn't want the leader to be going in the wrong direction all the time.
I'm bored, so here is my list of a fast killing, well rounded group, I wont go into to much detail because of the obvious, hell, the list itself is obvious
Sorc - ES/Orber or ES/Chant
Necro - Summoner
Amazon - Javazon
Assassin - Light Trapper
Barb - Concentrator
Druid - Windy
Paladin - Hammerdin
Extra - Zealot (Conviction or not) / Whatever you feel you're missing
It's pretty basic, but you have Light/Physical/Magic/Fire/Cold all covered, you are missing poison, but you don't really need. The Necro could just invest in LR for helping the elemental damage, since there isn't much physical going around. IMO, try to go mostly caster, since they are not so item dependent as melee (Spirit FTW). IM also won't be a problem. Insight should also be one the Sorc's Merc for teleport repositioning.
You'll have BO, Shout and Oak, lots of tanks (8 Mercs {Might/Def/BA/2 or so HF, rest Prayer}, Skels, Mages, Golem, Grizzly, Valk and Master), Concentration, Fanaticism or Conviction, and possibly Enchant all running at the same time for a solid party.
I'm still wondering which would be better though, ES/Orber or ES/Chant, ones more selfish so to speak, the other is VERY party friendly, but you don't want to just be chanting all day, so i'm leaning towards ES/Orber. Also maybe a Singer Barb for the Stun and non weapon reliance.
Sound good?