Update:How much does the electricity cost in your area?
Do not buy 270 cards, get r9 280.
My power value is 0.13 per kw.h so in 24h 0.13*24 = 3.12€/day ~93.6€ per month ~ 3-4 LTC
Stinky_Pete,I had realized that already, I'm probably going for 5 cards with 2 psu.
This post is exactly for probing the possibilities and finding the best investment!
I also voted investment

but people are too skeptical.
Everyone, As for costs/dates/setups etc:
atm I'm thinking core rig is
MotherboardAsrock X79 Extreme4 (7x PCIe slots)
GPUs5x VGA ASUS RADEON HD7770 1Gb DDR5 DVI DisplayPort - HD7770
(option to add 2 more)
Other components to be revisedCosts I'd say roughly 2000$ (max 2250$) per machine, initial investment is 1 machine
Dates: All I need is people interested imho ASAP should be the date!
I'm going on holidays so I have a lot of dedicated time to put to the rigging!
(aka NOW)
NOTE the setup is NOT final, It's still a work in progress and subject to changes like HD 7770 for R9 280 (for example)