+1 what jsc said.
The Corsair VX550 is a heavy duty power supply that is table and reliable.
You could use one splitter on 4 of the 8 molex connectors:http://www.google.com/products?hl=en&q=4+pin+molex+splitter&um=1&ie=UTF-8&ei=4xbLS-mqPJCisgOAkbnBAw&sa=X&oi=product_result_group&ct=title&resnum=1&ved=0CBoQrQQwAA
Here's a quick connect version that should work quite well since you can select where you want to added the connector along the length of the power cable:http://www.frozencpu.com/products/7616/ele-345/Standard_4_Pin_Low_Profile_Easy_Install_Connector_w_Cover.html?tl=g51c387
I'm surprised you are still using 4 pin molex connectors. Must be older hard drives. Just out of curiosity what are you doing with 12 drives?
Corsair and Seasonic are two brands that have a reputation for high quality power supplies that consistently earn high marks in technical reviews. They are reliable, stable, and come with a 5 year warranty. Some of the newer models come with a 7 year warranty.