I spent most of Sunday building the chicken tractor, and it's not quite finished yet, but my peepers are just fine in their heated brooder in the kitchen.
I built the tractor using (VERY roughly) the design from "Dark Dozens" in the coop photo gallery.
I built it entirely out of 6 foot cedar fence planks. I just need to finish fencing in the run area and add some wheels.
It turns out I'm the talk of the neighborhood, some of the older ladies that walk our neighborhood in the mornings and evenings have stopped by to see the baby chicks wandering around the yard or just look at the unfinished coop in my driveway, one even offered me a set of wheels from an unfinished coop she attempted to build a while back! Freebie!