The size does not matter. What matters is the energy, as you say. Mass is just a form of energy.
Just to rewrite what I said in other words, if you can produce such a thing at the LHC, it is produced in the universe since long ago as well. And also in our atmosphere where phenomena are occurring at an energy billions times larger than at the LHC at CERN.
Unfortunately, we have not observed anything at the moment.