FYI---For those interested in carbon fiber guitars but also like narrow or very narrow necks, it seems there is an easy option for you. Emerald Guitars can build the custom neck and this post from MacNichols forum shows an example of a 1 5/8" nut next to a Gibson with an even narrower neck.
http://macnichol.com/forum-post/4102
The X7-OS is similar in dimensions to the Cargo, but is slightly smaller, definitely lighter, and is louder. Tones are different though and some prefer one over the other.