Would you trust a Corsair HX750 to OC this rig?

Hi all,
I am upgrading my rig to the following:

ASrock Z68 Extreme7 gen3 mobo
Core i7-2600k CPU
Noctua NH-D14
2x4GB of DDR3-1333 ram
2x 7970 in CF (XFX DD BE + MSI Lightning)

I have two hard drives, no optical drive, 6 case fans, and about 10 USB devices attached.

My power supply is an HX750 at the moment, which I have been very happy with. However, would you trust it to deliver enough power to this rig once overclocked? I know that it is plenty to handle everything at stock, but I plan to run the 7970s at 1200 MHz core and the 2600k at as close to 5 GHz as I can get it.

My XFX 7970 requires 1.225V on the core to run at 1200 MHz, the lightning hasn't been installed yet but I assume that it will be similar.

Do I need to upgrade my PSU? I'm thinking that it might be able to handle everything but am just not sure. Really don't want to upgrade if I don't have to. If you think I do need an upgrade, what do you think of the Corsair AX-1200 as an option?

Thanks!

It's a Corsair...yes, I would trust it...but that seems like a lot to be running off of a 750 (still, it's a corsair).

You'll be fine.

What are these 10 USB devices? Here are my guesses what they could be...

1. Keyboard - (Mine actually takes 2 USB ports)
2. Mouse
3. Headphones w/Mic
4. Gamepad
5. Card Reader
6. Joystick
7. Printer
8. 2nd printer incase #7 dies...
9. Webcam
10. Profit.

Should be OK.
7970 is a 210w TDP, so 420 for the pair. A decent OC on both would raise that to maybe 500. CPU is 76w, solid OC on that gives maybe 150w. That brings us to 670.
HDDs are 10w each, USB devices are limited to 2.5w each (half an amp at 5 V).

Depending on how much the overclocked GPUs and CPU actually use it may be a fairly close thing really.
Really I'd run the GPUs at stock, you have to have a pretty wild display configuration to force you to OC a pair of 7970s.