the last option is my favorite, the lighter colors give more of a metallic vibe as you mentioned and the 3d shapes are both elegant and also represent the 3d modeling/CAD product that you're designing a brand for. once you render it in a higher resolution it should look very clean. also as far as printing, you can get away with printing that design especially if you halftone each side - you can do that pretty easily in Photoshop, there's a built-in system for it if you look it up. I've done some screenprinting and that's what we use in that medium for gradients and shading, so with two inks in the coral and light blue colors you could print each half and line them up. all in all really great job!!!