I'm sure you have your mind made up regarding what solar panels to use. But I was watching HGTV a few months ago and this guy from NYC built a totally of the grid home in Hawaii. He used Solar panels on his roof, except they looked like "Mats." He said they were customizable. So since he had a Metal roof, he'd run these Solar Panel Mats in between the Metal roof Panels. No need for Roof penetration or mounting hardware. You can order them with a special adhesive on the back. they range from 270 W to 315 W each mat. I think they're 18 ft by 19 inches. Here's the name (and there may be similar products out there):
GLOBAL SOLAR 270W-315W POWERFLEX+ BAPV FLEXIBLE CIGS SOLAR PANEL
www.continuousresources.com/