Autobot scout "Sledgehammer" turns into the weird little 2005 Magna/Steyr MILA concept car. Right arm is a Gundam Turn X-style multi-pod with a collapsible shield. I imagine it shifting and opening up to reveal all kinds of hidden weapons, claws, blasters and missiles, etc. etc.
Here is the car it's based on:[link]
I like that it's bright orange and has lots of mechy armor slabs all over it.
Made for a contest at TFW2005: [link]