Last year I bought a new bike that came with 700x38C tires and full length fenders. It had a coaster brake on the rear wheel and a very inexpensive single pivot sidepull caliper brake on the front wheel.
Over the course of the year I went from being a marginal cyclist to being a more committed and aggressive rider, and I made hardware changes to reflect that. I swapped North Road bars to drop bars, a twist shifter to bar end shifter, and fat tires to thinner rimmed wheels with narrow slicks. I took off the fenders because they rattled in the wind. My speed has drastically increased, but my braking power has not.
I installed a Tektro R556 dual pivot caliper brake on the rear brake bridge and it just barely fit properly with the pads set at the full 73mm reach. I'd like to have a more powerful front brake as well, and it seems more efficient to have a bigger wheel and normal sized brake. There is so much extra room with 700x28 and 700x32 tires mounted that I think I could actually switch to the bigger 27 inch wheels and use a normal short reach caliper instead of the long reach. I think the new style road calipers are marked around 39-49mm. Is the move from 700 to 27" wheels comparable to the difference in caliper reach from long reach to the normal range? I know most people go in the opposite direction and tire choice is more limited, but the overall proportions would seem more balanced. I wouldn't mind lowering the seat post accordingly. Anyway, is there a reason I can't get a bigger wheel and a shorter reach brake?