I've wondered if you could do this. My rear wheel has a nutted axle that's hollow. If you got a long quick release, like from a tandem, and ran it through the axel (after tightening the lugs, of course,) - would that hold a rack? You would have to spread the rack out, but that's easy to do. You would have to remove the rack whenever you removed the rear wheel, but that would only be a medium grade pain in the ass.

Come to think of it, you wouldn't even need a quick release. Hardware stores sell threaded rods. get a diameter that fits through the axel and cut to the desired length. Run the rod through the quick release and the rack eyelets.

For the top, they sell seatpost clamps that have you can attach a rack to. Or go to the brake bolt.