[100ideas]

I like your elegant thought experiment!

Quarks have -1/3 or +2/3 charge in the standard model and presumably(?) at high enough energies they separate out into a quark-gluon plasma thus exposing the universe to their unholy fractional charges. Above 2 trillion Kelvin according to wikipedia.

[zaarn]

Even with fraction, either you have repulsion or attraction, depending on the sign. -1/3 charge will be repulsed by +1 or +2/3 charge, just at different strengths.