In the spirit of a [related inquiry,](http://physics.stackexchange.com/q/7905/29216) I would like to know if there's a basis for understanding why there [aren't any elementary particles](http://en.wikipedia.org/wiki/List_of_particles#Elementary_particles) that have non-zero electric charge but zero spin?

Can such a quantum theory be written down and self-consistent? Do the current symmetries of our present QFTs not allow such a particle?