I've done it with an old Revenger-7. But I replaced the bridge and used an actual TuscQ 1-7/8" 6-string nut. The bridge is a Schaller 3d6, so I can adjust the string spacing at the bridge so the stings like-up better over the pole pieces. When I get around to doing a re-finish, I'll plug the tuner holes and re-drill just six so they all have straight string pulls.
It's the thickness/bluntness of the fingers that make the difference. There are folks with big hands that have thin and/or pointy fingers. If that's the case, then regular guitars are fine. Even if you've got small hands, if your fingers are thick, or very blunt, then you'll have problems. I've played a number of guitars where it's impossible for me to fret on the first 1-3 frets w/o damping the higher strings or having the lower string buzz against my nail. It's not poor placement, it's simply a lack of space.
Also, you've got folks that play electrics more like a classical/finger-style acoustic. There are plenty of 6-string classical and finger-style acoustics that have nuts in the 1-7/8" to 2" range.
As for demand, Warmoth and USA Customs make extra-wide necks. Soloway guitars can be make with wide nuts (Jim himself does/did play on 6-strings with nuts in the 1-15/16" - 1-13/16" range.). There's "Big Lou Wide Neck Guitars" that sells start & Tele clones with 1-7/8" nuts (he even sells 6-string 1-7/8" locking nuts and 1-7/8" and 2" necks). If you look at a lot of the custom builds threads at various sites, you'll see folks getting guitars with 1-15/16" - 1-13/16" wide nuts.
Now, as for demand for his do the bare minimum semi-monstrocities, I have a hard time seeing anybody, especially somebody that knows they want a wide-neck guitar buying one.