It's enough to dismay anyone, that's for sure. I'd love to have something like it though. If you were really into it, check out the Neve 1073 (I think?), learn how it works then see how best to adapt it to guitar. Would probably be easier than finding and tracing a Colour Box.
...errr, probably not, actually.
http://www.technicalaudio.com/neve/neve_pdf/1073-fullpak.pdf
...errr, probably not, actually.
http://www.technicalaudio.com/neve/neve_pdf/1073-fullpak.pdf