A bit of an odd question to all you current 17" PB owners. To carry a 17" PB around in my Tom Bihn backpack, I'd need to get a padded vertical sleeve for it (also available from Tom Bihn). The PB would be suspended vertically (one end facing down), as opposed to the spine of the PB facing down. Since the laptop would be lying against my back (not too flat there!) and the pack is tightened up across the shoulders and slung up tight by the waist, is there any chance that the PB would bend or warp over time across the short axis? How about the PB bending in general? Is it rigid enough to keep it straight and flat? Another long time Mac user suggested there might be "structural flex" for the 17" PB (he's a physicist) but he wasn't sure. Any durability problems that I should worry about? Thanks!