Thanks a lot for all those suggestions guys. However, I am complicated. Thran War Machine, Heraldic Banner and Welding Jar seem a little weak. Nettlecyst and Stonecoil Serpent seem a little pushed. Lodestone Golem and Monoskelion are already in the list. Others are too un-set-ish, too specific or require creatures.
However, the suggestions of the scaleable bodies and part-time-creatures made me think of this card, and I wondered, if you would count it as a card, that could work in aggro (as a curve topper) and control (as a finisher).
It might also very well just be too strong.
I might also just go for the Endless One. Not being an artifact is a pity, but it is pretty cool, simple yet flexible in how you play it.