You can get colorbond roofing that has a med grey up top, and light cream on the underside, and there are the ones that have the same color on both sides.
I don't think i've seen colorbond panels that have only one side painted.
I've come across local small businesses that will do a complete big pergola install, including plans, permits, foundations, etc, all for under $10k, where stratco will want over $20k for the exact same job!