The more I think about this, the more an eladrin hybrid swordmage/warlock fits the bill. You'd have good survivability and damage output. Lot's of movement and able to fill in for a striker, controller, or defender as needed.
Class abilities: aegis of assault and fey pact.
At wills: sword burst and eldritch strike
Feats: Hybrid Talent: swordmage warding, eladrin soldier, eladrin swordmage advance, fighter multiclass, fey charge, superior fortitude, improved swordmage warding
Other powers: suit to taste
Equipment: A pact blade longsword is must
PP: feytouched for lots of teleports, anarch of shyrr for extra basic attacks, wandering swordmage to boost other party members, or sword of assault to make good use of your defender mark.