Why DDR3-2000 ? if ya gonna use the unlocked CPU multiplier, are ya really gonna crank up the BCLK / mem multiplier to a point where ya need DDR3-2000 ? I'd get CAS 6 DDR3-1600 unless you have liquid nitrogen in mind.
I woulda said consider twin 570's which can be done with 8509 watter but with one already bought .....
For future dream build...since I don't know enough about Bulldozer, I have to go with Sandy Bridge.
i7-2600K OC'd to 5.4GHz
Whatever mobo goes with SB i7's & has a decent setup for 3 way SLI/Crossfire.
Corsair H70 cheap-0 liquid cooling (They say SB does 5.0GHz on air!)
3xSamsung Spinpoint F3 1TB in RAID5
2x Any Sandforce 128GB SSD's in RAID0
2x Any Radeon HD 6950 unlocked to 6970 & OC'd.
Everything else depends on what PSU's, cases & RAM are on sale on Newegg. Note: 8GB DDR3 (2x4GB) for upgrade to 16GB.
I think this build will nearly match the $4,000 one at the top, but for less than half the price. I'd save that extra $2,000 to upgrade to something else that's unnecessarily beastly in a year.