Well, I'm building up my 500 pt. list of Khador and I'll share what I have. Warning, I am not a master list builder. I have no idea if what I am building will be super great or not. I am also fielding three jacks which may not be the best tactically but I want to see what it can do. I'll give my reasons for this too.
Sorscha. Well she came with the box set and well she's Sorscha. (Altgough I have been playing with Vlad and loving him...more on him later)
Destroyer. Great model people underestimate his bombard cannon. I put 2-3 focus on him. I boost to hit, boost damage, and use the third to boost damage if I catch someone with collateral damage.
Juggernaught. Tough hth model. People fear him.
Kodiak. Can run without a focus. Can two handed throw. Can move thru rough terrain. lots of other goodies. I have not figured out to use him effectively yet.
Widowmakers. Because yes they do rock
Manhunter. Because he does rock too, but I have not learned to use him right yet either.
Mortars. They have really low RAT but they do give us some extra range and punch. I am not liking them that much tho.
Extra above 500 or would have to swap some things out.
I am thinking of using Winterguard. I dont see too many people using them. Iron Fang Pikeman are awesome.
Check my points, because I was just going off the top of my head.
Re: a second warcaster, I recommend picking one up because with a different warcaster you have a whole new battlegroup to play. Different spells, abilities, feats, etc...
Good Luck. If you are ever in northern NH come on up. We play at Empire Games check out our flex league here on dakka.