Riser Cable Decidement

Hey folks, I'm building a new rig, it's gonna contain 4 GPUs, my mobo (GA-990XA-UD3 (rev. 3.0)) has 3 16x and 2 1x PCIe slots..
I need ideas too choose a good cable.

As much as i could understand, I need;

• a 16x to 1x Extension Cable
  
• a Normal 16x to 16x Riser
  
• 2 16x to 16x Powered Riser
  

Okay guys thats it all, I wonder if there is anything wrong with the order and I wonder what's wrong with using Ribbon cable?
And do you recommend any websites for Turkey shipment?

edit:I thought it might be a good idea to buy a new Motherboard (Asrock ATX DDR3 1066 LGA 1150 Motherboard H97 ANNIVERSARY)
And I thought I can buy 4 1x to 16x extender cable and get the all power. Would this cause any problem?

Thanks..