New Crunching rack !NEED! Help picking hardware ..Please

[NerdLifeAMD]

I just took delivery of a 40u completely free. and he offered to make me a second if i ran some network line at his home got me thinking????? well almost free traded my time nothing more so its on to hardware ive been looking at whats available at new egg and man a lot of choices all dependent on other choices. these are my issues. when i first decided to build a rack to crunch on I had top of the line in mind now that its time to pic out hardware im not so sure? i cant ignore the fact that i can get two 6 ways for the price of one 8 way just for an example? or that i can get two very nice asus bords with only one pcix 16 slot for the same price as one with two? or that i can get 2 4u cases that the only complaint is they r flimsy for the price of one nice steel case. i mean they will be in a rack who cares if they are flimsy ? ive had great luck unlocking cores also which is something to consider ... my last 4x unlocked to 6X and clocked to 4.2 with an aftermarket cooler but those phenom chips are getting pretty old also i havent really played with the desktop apus but im told you can crossfire them with a independent card all in all i was intending on 4 or 5 4u blades now im thinking i could build 8 or 9 i mean 40 cores in nice but 54 or maybe even more is better for the same price if i do it smart. id like some help getting a cart together am very very serious i just took a second job for the extra funding start on Monday so with the thought that 12 cores are better than 8 for the price starting the cloud in my head i look for inpu.t chip decision will be the first thing i need help with ???? and the decision to build 4-5 high end vs 8-9 very decent computers? the reason 9 not ten is to leave room in the rack for a rack mount router anyway thaks for any input in advance talk nerdy to me

LET ME JUST ADD POWER CONSUMPTION IS NOT AN ISSUE

I HATE WAITING ON RMAS lets get it right the first time