[simonh]

I don't see how that would work with length contraction and time dilation. A unit quantum length object in my frame of reference would have different length to one in a frame at motion relative to mine, and time for it would pass at different quantum clock ticks. I don't see how a universe like that could work when it came to interactions between moving particles.

[AnimalMuppet]

You're assuming that the Lorentz contraction applies unchanged as you move to the Planck length. That's not a given.