The Planck energy limit is 1.2*10^31 eV, converting this into temperature we get approximately 1.3*10^35°K the highest temperature commonly encountered is that of the fastest cosmic ray particles of 10^20eV
Planck energy should be ~ 1.22*1028
eV, according wikipedia:http://en.wikipedia.org/wiki/Planck_energy
so the max temperature should be ~ 1.4*1032
K (using, as you did, the relation E = kT with k = Boltzmann's constant = 1.38*1023
Yes, the more energetic particle we have detected (the famous "Oh My God! particle") is that one. However, it's impossible to attribute a temperature to a unique particle: we need many of them with a Planck distribution of energies, to do it.
Example: you know that a blackbody at room temperature emits EM radiations of many frequencies = energies, even very high ones (but with very low intensity, of course); if you analyzed only those very high frequencies, for example with a filter, would you conclude that the body's temperature is very high?
Actually, kT can be associated to the average energy of a particle, so, if Planck energy is the max energy, then the average one is much smaller (which means that limit for T is too much optimistic!)