Advice for large computer

Alrigt, I've been planning on making a computer with a custom case, and top-of-the-line things inside. Problem is, I'll be building it two years from now. But thats not the problem. My problem is that I want to cool it without too much risk. I've already decided to lay the mobo horizontal to prevent the (most likely) heavy copper heatsink from straining the proc. But, I want a wat to get SLI's GPU's as far away from the machine as possible. Are there an risers that move SLI'd cards far enough away form the mobo as to not interfere with the north/southbridge?

Also, I want to get a sole power-supply for the GPU's, and the other PSU for everything else (HD's, optical drives, CPU, mobo...). Is there any wat to do with efectively? Since I'm thinking with the GPU's far away from the mobo, cables would need to be incredibly long to reach. Thats not friendly for the power flow form what I've heard. Any ideas on the whole thing you may have would be great.

No stupider than the initial question. If computers couldn't be cooled safely and effectively with off-the-shelf kit we'd all be up shit creek. And who knows what stuff will be available two years from now?