My chaos army has a renegade blood angel theme. They've made contact with a few Traitor Legionnaires, who they are learning the true nature of chaos from.
I've used a few
DV miniatures in the army. Some are un-modified and just painted to suit my army themes (chaos details are added through paint/transfers).
Most have backpack swaps and have their shoulders redetailed.
Some have extensive re-working (swapping out the front plate of the armour, chaosifying weapons, heads and arms).
These are recent additions to my army and the pictures aren't up to date so they still have some work before they are finished.
Don't forget many chaos marines rely on piracy and looting to keep their equipment running. There is no reason your chaos marines won't be wearing hastily repainted Dark Angel armour if they're currently fighting a campaign against Dark Angels.