In my opinion there would be room for a kind of Sweboz berserkr unit, similar to Celtic Gaesatae (from which we also know very little), perhaps a little weaker. The problem with the Germanics is that we have nearly no knowledge of military things and much other like names or social order prior to the 1st century BC (beside the few weapons et al. findings in graves etc.). Many features of the Sweboz are educated speculation, based on later Germanic military features. Because berserkr were a common feature of later Germanic military, this knowledge could be used for the creation of a Sweboz unit too. Some units in EB 1 (Wild men or this black skinned unit? sry, never played as Sweboz) could be a starter.