Here are some great brakes that will fit a lot of cruisers with 26 wheels on both ends:
I got a pair awhile back- they look even better than in the ad- the anno aluminum is brilliant red- looks like a christmas ornament, and lost in the picture
the back will generally fit a 700 or 27 wheel in the back too- but the reach is too long then on the front brake- a shorter one is needed then.
the hardware for the brakes- pads and center pivot and bolts are usually a lot of this total cost if bought seperately. If you search a similar design for roadbikes- the price is much much higher.