A few points to consider-
*Keep air flow in mind. A well ventilated show barn can have a drastic impact on energy costs and cut down on fans needed.
*Have pens that don't have concrete floors. As FSSR said, using mulch/fiber over natural flooring is best. Putting one on concrete is a sure fire way to kill their joints.They have to be on concrete plenty as it is with clipping, washing, ect.
*Make areas dual purpose. A wash rack (with the set up FSSR mentioned) can also be excellent for clipping. I also like a wash/clip area that you can easily roll a steel fitting chute into. That way, they are a bit more secure for that first bath or two.
*Keep lighting in mind. Especially in your clipping area, where zero shadows are the goal.
*Plan for pleny of power source points, that can carry the load of blowers, fans, clippers, ect. all at the same time. The best thing we ever did in our barn was wire in extension cords that hang on retractable spools from the ceiling! They are easily accessible everywhere in our barn, and provide power without cords laying on the ground. No worry of them getting tangled in a calf's legs, shorting out in a puddle, getting in the way of cleaning, ect.