the reason for the Qs is that a coiler and stinky both are "ride to the top" bikes and the only shuttler Kona makes is the Stab. of course you could build a stinky heavy enough to mimic a stab but then it really wouldn't be a stinky any more would it?
the reason my questions are blunt is because this isn't an emotion-based decision, it's a factual one. cut out the fluff and we find what we need.
do you currently avoid technical terrain like Gore Mtn on your HT? or would you go ahead and ride the HT there, but wish it had more cush?
the main reason for this Q is that it's surely possible to make a HT perform well in DH conditions for the occasional shuttler, and if you're limiting yourself to $1500 or even $2000 you can get a much better HT for the $$. I'm not talking about your Caldera. I'm talking about something more like an Evil Imperial or similar burly HT frame.
also, have you ridden any of the bikes in the 4"-6" rear travel range? for DH and FR there are only really 3 basic designs out there, each with its own (+) and (-) factors. the few basic proprietary weirdnesses are going to be outside your price range anyway.
If you were trying to build a burly and inexpensive bike in the 4"-6" travel arena I would suggest using the Banshee Chaparral frame, which is adjustable among 4" - 5" - 6" rear travel settings. it is extremely burly and will not fail on you. you can build one to resemble a light FS trail/XC rig, or a burly 6" travel rear FR rig. in other words, you could build an inexpensive but strong model right now, and then as you find out what you like or don't about FR/DH, you can reconfigure when parts break or wear out, which is bound to happen if you end up riding lots of lift-served or shuttled mileage.
Banshee's 4-arm rocker design is very similar to the design Kona uses on the Stinky & Coiler. it's a rocker-arm actuated single-pivot system. such systems give up a bit of braking plushness to give much higher lateral rigidity throughout the suspension travel. I like these systems and have two FS rigs using that design (Banshee Scream and Ventana X-5).
you could look around a lot more, you'll hear recommendations for all kinds of stuff, but in the end, for what you want, the Chaparral is best.
a 2d choice -- if you can spend a bit more $$ -- is the Ventana El Chamuco, frames are about $1300.