Well I have modified my Kelty Trekker. Most noticeable is the lack of a waist belt, and suspension transfer system. I've also removed exterior side pockets, mesh waterbottle holders, and trimmed lashings. Believe it or not it's still comfortable with 20lbs. I have yet to test above this weight yet however (more to follow on this). It's incredibly stable too. I love how everything cinches to the frame, and it's like one solid mass, instead of a globule of flexing media. I'm thinkning of making a one-off aluminum tubed external frame pack. Instead of interlocking U-Tubes, it would be one solid custom curved oval-like frame reducing weight even further. Next august/september I will be thru-hiking the long trail (S to N), hopefully I'll get all my custom gear done by then!