so tubus makes these overpriced QR adapters that conveniently has 3 holes in them. https://www.google.com/search?q=tubu...w=1280&bih=620

what if I did something like this

it will distribute the forces a lot better than just p clamp or qr skewer alone... most of the compression is on the skewer. the p clamp on the seat stay serves the primary purpose of keeping the rack in place when you remove the rear wheel. It will experience much less pulling force than the skewer. the only trick is how to get around the disc brake.. perhaps another p clamp on the rack.. what say ye?