That guitar Steve Vai promotes.. I think it's a Ibanez JEM is also quite versatile.. unfortunately I haven't had the chance to play one so I don't really know.. but reading the reviews by other people and Vai himself, it just seems like it would be a guitar worth adding to any rock guitarist's arsenal.. I may be wrong though. :)

Also there is that Fender Stratocaster VG thing that has the Roland bridge pickup so that it can emulate/model about 7 different tones (ie. Strat, Telecaster, Humbucker etc) and also set tunings at the flick of a switch (Drop-D, DADGAD, Open G, Baritone, and one other I can't think of right now.. as well as standard). I think the VG retails for about $2,500... worth checking out though.. but in other discussions here on GT it has been pointed out that something like this guitar may potentially depreciate in value faster than a vintage or custom fender would.