You don't need dummy plugs.
Also, you might wanna get better cards than the 270's. It's going to take you a while to make your ROI with those cards.
What GPU then? ROI calculations say under 3 months, so not bad. IF there is a way to improve that, I be glad to hear. Why do I not need dummy plugs? Running Ubuntu if that helps.
Go with 270X HIS cards from newegg.. they are around $200 bucks. Dump the SSD and save the money. Grab a USB thumb drive and load SMOS linux on it for free. Get a Gold rated power supply, dont skimp here.. Newegg has good ones for decent $$$.
Running Ubuntu so mining OS are out of the way as im using a wifi connection with a cheap USB wifi stick. IF there are mining OS that support WIFI or able to run Ubuntu off a USB stick, it be great if you could link it in a future post.
Any links on how to configure multi GPU mining on Linux using cgminer,bfgminer, etc. would be great also!