I think a lot of intonation issues were solved with the fan fret guitar necks but it is impossible to eliminate them all, interesting though and see how it's applied through the entire C Major scale. Whether a vocalist can match those pure notes w/o warbling is the other question. Something like this would make all the other band instruments sound slightly out of tune. I would seriously hate to have to tune drumheads to pure notes by ear. I think it would be impossible for this in real world applications. Guitar strings would never last for more then a few strums/picks, put a dent in a drumhead and there goes that (if you can tune it pure at all to begin with) etc...
Guitar players don't really care about stuff like this unless your trying to play in multiple scales, hence intonation becomes a problem due to the limitations of standard fretboard design and intonation of individual strings. This is why multiscale guitars were designed and the fanning of fretboards comes into play (I have seen some seriously extreme fanned fretboards)
Do you notice some of the most beautiful sounding singers in the world warble on extended notes? It's a pleasing affect