Edit: I misunderstood.
You're essentially suggesting that something akin to Hammer units exists in the real world, yes?
What you're saying is actually already a leading theory.
AFAIK, the reason nothing can be physically less than a planck unit is because a "planck" is the limit of some mathematical function that explains one very important aspect of the physical universe. Mathematically speaking, nothing could physically exist beyond that point because the function simply can't calculate any further.
So we can theoretically say that something is a "half-planck" in length, but the conditions for such an object couldn't exist under our understanding of physics--thus we say such an object couldn't actually exist.
I'm no physicist, and this is probably wrong.
Edit edit: Here's some food for thought, though: modern physics suggest that many things in the physical universe--matter, light, radio waves, dark matter, etc.--is comprised of the same type of energy. The only thing that makes them different is density of energy. Matter is supposedly the most dense form of energy.
Antimatter is one form of a second type of energy that seeks out matter like a magnet. When the two meet, they both dissipate.
More food for thought:
A neutron star is a dead star comprised of only neutrons. The neutrons stick together like a sphere made of marbles, so a neutron star is literally as dense as matter can physically be.
BUT in the deaths of super-massive stars, the force of gravity actually overcomes the dense cluster of neutrons, and the neutron star collapses on itself--like a chair that collapses under the weight of a fat guy. And since there's nothing left to "break the fall" after these neutrons are crushed, the neutron star keeps collapsing until it has zero volume. A black hole.