The new Land Raider Achilles from Forge World inspires an interesting concept: running an Adeptus Mechanicus army with Codex: Space Marines. The HQ choice is obvious: Master of the Forge. Him and his retinue of Servitors can ride in the Achilles pattern Land Raider as a Heavy Support choice. The other two Heavies could be Thunderfire Cannons. Three Thunderfires ain't nothing to sneeze at. More Land Raiders would also be a nice addition. Dreadnoughts as desired in Elites and Heavy. Token tac squads for Troops. Land Speeders make sense for Fast Attack. The more vehicles the better. If you're feeling especially ornery, take all three Heavy slots as Achilles, MotF in one and a Techmarine each in the other two.
I'd argue for adding a special character that allows Servitor squads (we can't just leave it as a single 10 point Servitor in a squad, though) in Troops. Use Techmarines as sergeants for them (making it 4 Servitors + Techmarine in a squad). Even leaving the Techmarines as Elites would work (just not all that well). Allow Razorbacks as transports for them.
But seriously, where are the Ad Mech shoulder pads, GW? I guess we'll have to settle for raiding the bitz shops for them off of the LR Crusader sprues. That gets you torsos too! I'd still like to see some Ad Mech marine kits from Forge World, though. Grumble grumble.