Something we've been wanting since, well Dawn of War was announced, a true TechMarine. These bad boys aren't your typical pansy builder units. They have their own ways of brutally disemboweling the enemy while fixing your Land Raider for you. The two Tech Marine variants are:
1) One that replaces the servitor and is armed with a bolter and servo-arm. No upgrades.
2) One that takes up Elite cap, can have a bunch of upgrades and a retinue of combat servitors. Cannot requisition buildings, but he can construct/repair them.
These bad boys are already in-game for the internal beta testers and man they are nasty. All we need is some textures on them and they will be good to go.