If I was over confident, or unethical, or both I would say "sure". Given that I'm neither and haven't finished one of my own yet, I'd say it would not be the honourable thing to do. What if my current projects turn out looking great but sound awful? What if the body starts to come apart or crack after 6 months of string tension? What if you keep tuning the strings, only to have the bridge pop off of the body? What if it sounds good, but only up to the 9th fret or so because I got the scale or intonation wrong? There's a LOT involved - mechanics, physics and believe it or not, geometry, and that's without even knowing the characteristics of wood. I have religiously followed the design principles, but my work is unproven.
If it helps, you are probably one of the people here that I would entertain the idea for, but I would feel very bad if the instrument didn't work out mechanically or vocally over the long term. If you want to wait, we can see how my current 2 projects pan out. One is a 000 (Auditorium) waiting for finishing then bridge/nut install and the other is a dreadnought, both 6 strings.
I still have top, neck and bracing material to spare and a nice set of East Indian Rosewood back and sides waiting in the wings which might become a 12 string if I don't have any other pressing need for!
EDIT - if anyone reads this and wonders why I would make a ukulele for someone then, it is because I had the advantage of having done one already from a commercial kit. All I had to do was replicate that kit and its design, which I felt I could do. A full size guitar is in a different league and the forces created by steel strings of that length are in another category.