I opened up my case last night to see what I could do far as routing the cables behind the motherboard. Unfortunately for me it is not going to work out. The 24 pin main power cable for the motherboard off of my OCZ GameStream PSU is really thick. And there is not much room at all on the back side of my Cooler Master Centurion 534 case. I tried last night to get the cover back on the case with the power cable behind it and I could not do it without bending the cover. The cable is way to thick.
However I did see how I could route some smaller cables out to the way thanks to the ideas that have posted on this thread. This has been a great thread so far.
Hey, has anyone seen the Ultra X-Connect power supplies? I think they got the best thing going. These are modular power supplies and all of the cables lay flat, even the 24 pin main power connector. Take a look at the link below and scroll to the bottom of the page where they have all of the cables layed out.
http://www.ultraproducts.com/product_details.php?cPath=97&pPath=632&productID=632
My wife has had one on her computer for going on 3.5 years now and it has worked great. These cables are very flexible and there is a lot you can do with them.
I think my next power supply will be an ultra. And I think my next case will be a NZXT Tempest.