Quad-SLI GTX 680 & i7 3960X PSU Recommendation

[sk3tch]

Hey guys,

I'm building a boss hog box...I have all of the components except a suitable case and I believe I need a better PSU...here's what I have thus far:

i7 3960X overclocked
Corsair H100 liquid CPU cooler
MSI Big Bang XPower-II mobo
32GB Mushkin Redline RAM
1x 256GB Samsung 830 SSD
1x 512GB Samsung 830 SSD
4x EVGA GTX 680 overclocked

All would be on a Cooler Master Silent Pro Gold 1200W - from a wiring perspective, it works - except I can't power the add'l VGA power connector on the mobo itself (it's a high-end OC board so it has more juice for CPU/VGA on the board for OCing).

Should I go to a bigger and/or better PSU?

Silverstone Strider 1500W?
Platimax 1500W?
MaxRevo 1350W?
Seasonic X-1250?

Thanks!