this all very rough and ready, btw:
Ultramarines
Scout
Tactical Marine
Assault Marine (w/jump pack!)
Devestator Marine (w/missile launcher)
Terminator (power fist + storm bolter)
Veteran Marine (power armour)
Bike
Attack Bike
Land Speeder
Land Speeder Typhoon (rocket launchers)?
Predator Destructor (autocannon truuet)
Vindicator
Whirlwind
Land Raider
Rhino
Dreadnought (power fist+storm bolter & multi-melta)
Razorback
Blood Angels
as Ultramarines, but...
...swap Veteran Marine for Assault Veterans (jump pack assault)
...swap Predator Destructor for Baal prdeator (twin assault cannon turret)
...swap Dreadnaught for Furioso Dreadnought (two powerfist+storm bolter, colour should be black)
...add Death Company
Dark Angels
as Ultramarines, but...
...swap Terminator for Deathwing (different model)
...swap Bike for Ravenwing Bike (different model)
...swap Attack Bike for Ravenwing Attack Bike (different model)
...swap Landspeeder for Ravenwing Landspeeder (different model)
Space Wolves
as Ultramarines, but...
...swap Tactical Marine for Grey Hunter
...swap Assault Marine for Blood Claw
...swap Devestator Marine for Long Fang (hvy bolter)
...swap Veteran Marine for Wolf Guard Power Armour
...swap Terminator for Wolf Guard Terminator (chainfist+storm bolter)
...swap Dreadnought for Venerable Dreadnought (lightning claw+assault cannon)
...swap Scout for Wolf Scout
Black Templars*
as Ultramarines, but
...swap Land Raider for Land Raider Crusader
...swap Predator Destructor for Predator Annihilator (lascannon turret)
...swap Land Speeder for Land Speeder Tornado
...add Emperor's Champion (should be really expensive, since there's only supposed to be one at a time)
*I know I said Imperial Fists, but do you know of any units for them?
Besides, the Templars are 'descended' from the Fists
N.B. All Guard armies will need their own units - catachan guardsman won't do for a Mordian civ
Catachans
Catachan Devil
Deathworld Assault Team (demo charges)
Deathworld Sniper (invisible, hidden nationality)
Jungle Fighter
Fire Support Team (hvy. bolters)
Ogryn
Deathworld Sentinel (hvy. flamer)
Mortar Team (umm...mortars...)
Booby Trap (immobile, airdrop, cruise missile)
Mordian Iron Guard/
Guardsman
Fire Support Team (hvy. bolter)
Comm-link (radar unit?)
Ratling Sniper
Ogryn
Rough Rider
Chimera
Leman Russ
Demolisher
Basilisk
Griffon
Hellhound
Sentinel (multi-laser)
Commissar
Hydra Flak Tank
Baneblade Super-Heavy Tank
Shadowsword Super-Heavy Tank
Armageddon Steel Legion*
as Mordians, but...
...swap Fire Support Team for Anti-Tank Team (lascannon)
...swap Sentinel for Armoured Sentinel (lascannon)
...swap Guardsman+Chimera for Mechanised Infantry
...swap Basilisk for Medusa
...swap Leman Russ for Leman Russ Vanquisher
...swap Baneblade for Stormblade
*I know I said Cadians, but these guys look like WWI soldiers in trenchcoats and gas masks!
Valhallan Ice Warrios
as Mordians, but...
...swap Fire Support Team for Artillery team (mortar)
...swap Basilisk for Manticore
...swap Leman Russ for Leman Russ Exterminator
...swap Baneblade for Stormhammer
Adeptus Sororitas
Battle Sister (power armour, bolter)
Hvy. Battle Sister (hvy. flamer)
Seraphim (jump packs, assault trrops)
Frateris Militia (cheap, conscript, draft units)
Rhino
Immolator (twin hvy. flamer on armoured rhino chassis)
Tarantula (flak weapon)?
they should also have access to Imperial Guard units
common to all Imperials
Warhound Titan
Reaver Titan
Warlord Titan
Imperator Titan
Chaos
Raptor (jump pack)
Obliterator
Havoc (devestator)
Dreadnought
Predator
Land Raider
Rhino
Bike
Possessed Marine
Cannon of Chos (uses the Cannon of Khorn model)
World Eaters
as Chaos, but...
...add Beserker
...add Beserker Terminator
...add Bloodthirster
...add Bloodletter
...add Flesh Hound
...add Bloodcrusher (beserker on juggernaught)
...add Brass Scorpion*
...add Blood Reaper*
...add Death Dealer*
...add Cauldron of Blood*
...add Tower of Skulls*
...add Lord of Battles
...swap Warlord Titan for Banelord Titan
...swap Cannon of Chaos for Doomblaster
*I suggest we pick one of these
Emperor's Children
as Chaos, but...
...add Noise Marine
...add Noise Marine Terminator
...add Keeper of Secrets
...add Daemonette
...add Fiend
...add Hellish Cavalry (Daemonettes on Steeds of Slaanesh)
...swap Reaver Titan for Questor Titan
...swap Warlod Titan for Subjugator Titan (smaller & not as tough)
...swap Warhound Titan for Hellknight
...add Hell Scourge
...add Hell Strider
Death Guard
as Chaos, but...
...add Plaguemarine
...add Plaguemarine Terminator
...add Great Unclean One
...add Plaguebearer
...add Beast of Nurgle
...add Nurglings (cheap draft unit)
...swap Cannon of Chaos for Contagion (mobile catapult)
...add Plague Tower
Thousand Sons
as Chaos, but...
...add Thousand Son
...add Thousand Son terminator
...add Lord of Change
...add Horror
...add Flamer
...add Disc Rider (rider shoots sorcerous bolts)
...add Silver Tower (skimmer unit - mobile aircraft?)
...add Doomwing (flyer - interceptor)
...add Firelord (flyer - bomber)
Necrons
Warrior
Pariah
Immortal
Flayed One
Wraith
Destroyer
Scarab Swarm
Tomb Spider
Heavy Destoyer
Monolith
Tau
XV8 Crisis Battlesuit
XV15 Stealth Battlesuit
XV88 Broadside Battlesuit
Fire Warrior
Pathfinder
Kroot Hound
Kroot Carnivore
Krootox
Devilfish Troop Carrier
Hammerhead Gunship
Barracuda Air Superiority Fighter
Tiger Shark Bomber
Dark Eldar
Warrior
Reaver Jetbike
Hellion
Warp Beast
Grotesque
Mandrake (invisible)
Wyche (assault troops)
Incubi (well armoured, armed & trained!)
Scourge (jump packs, hvy. weapons)
Raider Transport
Ravager Gunship
Talos
Raven Fighter
Ravenwing Bomber
Barrage of Torturous Delights
Shadow Stalker Titan
Tyranids
Hive Tyrant
Lictor
Tyranid Warrior
Genestealer
Termagant
Ripper Swarm
Hormaguant
Gargoyle (small flyer)
Harridan (v. big flyer)
Ravener
Carnifex
Zoanthrope
Biovore (light artillery)
Exocrine (hvy artillery - cannon)
Dactylis (hvy artillery - catapult)
Assault Spawn (also a transport)
Dominatrix (the hive queen)
Hierodule (smaller titan)
Hierophant (larger titan)
I'd do more, but I can't be bothered