A Monte Carlo simulation of electron transport in the conduction band of diamond as a function of field and film thickness has been performed. It predicts that the energy distribution of field emitted electrons "heats up" when the internal electric field is of the order of 1 V/mu m and greater. The energy distribution shifts and becomes broader as the width of the sample increases. With increasing field (greater than or equal to 10 V/mu m), there is a transition to quasi-ballistic-like behavior. For thinner films (less than or equal to 0.1 mu m), the transport is more clearly ballistic with the peak energy scaling roughly with the field. It is suggested that if a realistic and viable electron injection mechanism into the conduction band of a diamond-metal or diamond-semiconductor interface could be found for those crystal faces of diamond exhibiting negative electron affinity, then a copious cold cathode electron emitter with field tunable energies is feasible.