I wouldn't even know where to begin with that kind of money for a rig!!
If i had $15000 for a build, I'd start with a 93-7 Ranger for under 1500. The remaining $13,500 could probably get you a nice sas front with coil overs (I'm partial to the TTB though, but it's only good for so long), Explorer disc 8.8, some air lockers/ gears, a doubler, a cage/ sliders, some 35's and an Exploder 5.0L. And throw in an 04-up nose swap for the hell of it. I doubt that would even come to the $15,000 total, if done with cost in mind. If it went to a shop, I don't know what you'd get.
That'd be my rig. But in reality, I'd never spend half that on a rig. Not all at one time anyway.