Khaki is no longer available in 4x ... the choices have narrowed down to navy, black, or camo. Since the Ghostbusters II uniforms were dark grey, I went with navy, figuring that was the closest match. Khaki can still be found in 3x, but given how pinchy the 2x was, I don't want to risk it.
Also, ecto-goggles have been ordered. :) The uniform will probably be complete by the end of July -- so I can start thinking about how the heck I'm going to ship a proton pack around the country without it getting destroyed. O.o