I'm using the Tubus Fly rack and Ortlieb Back-Roller Classic panniers on my Specialized Tarmac for the PCH later this month. Contact Wayne at thetouringstore.com. He is extremely knowledgeable. For most competitive calipers you'll have to remove the brake and attach the rack on the recessed allen nut.

Or, check out Epic Designs and Carousal Design Works. They have some sweet seat bags that I would have loved to use but I put my trip together kind of last minute.