After much searching I couldn't really find a relevant frontal area number for my 2005 Accord, so I found technical drawings on the-blueprints.com that lunarhighway mentioned above. They're not the exact same trim (I don't have the foglight recesses or the side mirror reflector/indicators), but it looks close enough.
Put it into Photoshop, selected the area of the car, then looked at the histogram (in CS5.1, Windows -> Histogram) for the number of pixels. Oddly, the number of pixels reported in the histogram is significantly less than the actual number of pixels you get when you multiply the dimensions of the image, however after adjusting for that, I got 23.8 square feet as a frontal area, which isn't far out enough to be obviously wrong at least.
Removing the side mirrors apparently lowers this by 2.5%. Neat.
