What so you do when you get a new bike and find that it doesn't fit on your old Yakima Steelhead rack because the disc brake caliper gets in the way?
You can drop $150 and get a fancy new rack.... Which of course only works for one newfangled bike, so don't try to bring someone else along.
Or, you can get a hacksaw and a file and start cutting away. I think the result looks pretty good.