I'm trying to price out a multi-GPU rig for hashing sCrypt. I'm a comp-sci major and I'm A+ certified for hardware, but this is some stuff I haven't really done before (that's why I'm in the newbie forum).

I've been running the numbers, but I'm having trouble figuring out exactly what I need to buy.

My current shopping list is:

Motherboard with 4-8 PCIE slots
3-8 GPUs based on whatever I can find cheapest on this chart I made (http://i.imgur.com/9X4jV0O.jpg)
Powered PCIE risers
PSU(s)
CPU
HDD
RAM

I already have a stack of RAM and several cases (including a large server case), at least 1 spare HDD, and 2 PSUs sitting around.
So, what remains is trying to find an appropriate mobo, and figuring out the total Wattage of the system.

Also, I need to figure out which cards/boards/etc are voltage unlocked....

Uh...HALP!

I'm finding it very difficult to find resources on searching/sorting mobos based on #PCIE slots, and not finding tons of info on what components are voltage unlocked and how that will/could affect the total wattage of the system.

Also, I saw several references to running multi PSU-single-mobo systems - how do you even do that?

Does anyone have a simple guide on who to configure a DIY system like this?