For coloration without resort to image maps - for that distance to the giant planet you don't need an atmosphere (on the giant), whose thickness would be small compared to the planet size. Put color right on the planet, you could try a surface layer of one color and a surface layer of a second color, with the latter having a blending shader that masked part of the overlying layer. In the blending shader, stretch the noise (perlin will do) in the x and z directions but not in y. This will smear the noise in the mask in the equatorial direction on the planet (y being aligned with the planet poles). Push the color offset toward black to get some masking. Thus you have the basic banding. Set the scale of the noise in the blender to be roughly 1/10 the planet diameter or whatever size you want the bands. From this basic approach you could replace the solid color of the surface layers with color power fractals inputed to the child layer of the surface layer node. The detailed look of Jupiter-style cloud band intermixing is another and harder story. I think cyphyr figured it out. -Bill
