I'm surprised no-one thought of this before.
Scout - Scout with Combat Shotgun
Soldier - Tactical Marine with Missile Launcher
Pyro - Tactical Marine with Flamer
Demoman - Assualt Marine with Frag Grenades
Heavy - Devastator Marine with Heavy Bolter
Engineer - Techmarine
Medic - Apothecary
Sniper - Scout Sergeant with Sniper Rifle
Spy - Scout with Combat Knife