Note: This was done in v1.00. Use the following trick to get more units than you normally do in that unit or set. For example, if there is a cohort of 81 troops (this should work for any number of troops regardless of type, culture or unit number setting), if 70 are lost in battle bring them to a settlement that can retrain them. Add them to the retraining query, then drop another full cohort of that type on the retraining cohort so that the retraining query displays the complete amount that the cohort is supposed to have. Then, end the turn. That cohort should now have 151 units in it.