Were it not for the lack of Unify Colours on companions right now, I'd direct you to the Tx-16a range: Powered Assault, Tech and Havoc, all at about level 42. There's also the Electrum Onslaught armour set at 50, which is a match for the Phalanx set. Closest match to the outcast would be the Havoc, which is white with yellow highlights (and looks to match the lower-level Raider armour set as well).
I'm not aware of anything available at a lower level, but somebody else might be.
Pretty sure I can unify my companion colors the same way I do mine.