One of the more interesting bicycle races of the year does exactly this: the Little 500 (https://en.wikipedia.org/wiki/Little_500 https://en.wikipedia.org/wiki/

One of the more interesting bicycle races of the year does exactly this: the Little 500 (https://en.wikipedia.org/wiki/Little_500 https://en.wikipedia.org/wiki/Little_500) All the bikes are identical in spec (single speed, coaster brake, flat pedals). This is the race that features in the movie Breaking Away. I wish more were like it, but I guess part of its charm is its uniqueness.