Very interesting concept. You indicate it interferes a little with using your poles; you also infer it's not well balanced, side-to-side, since it's all on one side (but you change shoulders.) What if you took it a step further, and mimicked the Civil War photos: bedroll over one shoulder, with a haversack over the other shoulder? Your bedroll could consist of your shelter, bag, pad, spare clothes, and maybe tomorrow's food. Your haversack could hold today's food (maybe tomorrow's, too?), your stove and fuel, map, compass, water treatment, and other small items you might want easy access to. It would also put perhaps half the weight on each side. I'm thinking something like a large Granite Gear Air Space box-shaped, zippered, stuff sack with a webbing shoulder strap would make a good haversack - you could also build one yourself, with two or three sections to allow you to organize things a little. (Of course, the haversack would add 3 or 4 ounces to your kit; maybe it could justify its weight by stuffing clothing in it at night to form a pillow?)
A Platypus could go in the haversack, or simply clip to your belt.
Another thought on pole interference: you could try using only one pole, switching hands as you switch shoulders.
Neat idea - let us know how it works out.