although I actually like the "shred" guitar necks like the Ibanez wizard, which has a nearly flat fretboard radius and a slim back contour. But even the "shred machine" Ibanez, Jackson, Charvel, Fender Talons, etc. aren't quite wide enough for me, as they usually are at 1 11/16 inch nut width. I have somewhat small hands but I find that a wide neck with wider string spacing is easier and faster than a narrow neck of most standard electric guitars (which seems even narrower when you spend a lot of time playing on the neck of a classical guitar).
You might try something like USA Custom Guitars, where you can order both a guitar neck and body to your specifications. You can even get it as wide as 1 7/8 inches and have the back contour as fat or as slim as you want and shaped the way you want (U-shaped like a shred guitar, C-shaped like Gibsons, V-shaped, soft V, etc.). The only problem is that it will be a bolt-on style neck (like Fenders) as opposed to a set neck or neck through body. I think the PRS guitars might be set necks but I'm not sure. This supposedly affects sustain but some claim that it isn't a factor if the neck heel and the body's neck pocket are a real tight match (which a custom maker is supposed to get right). And if you do most of the assembly yourself, it probably won't cost you that much more than a moderately priced brand name guitar.
Here's a link:
http://www.usacustomguitars.com/