Fatshark have said that they looked into creatures like chaos warhounds (who could be in both the Chaos and Beastmen roster in Vermintide), but that they are a lot of work, so it almost sounded like a no. That stream isn’t watchable anymore, so i can’t show you, but they reacted to someone asking in the chat. So there’s that.
A Razorgor/Tuskgor could be an interesting second Boss for the Beastmen, a big variant should have the same size as the others (heigthwise similar to Chaos Spawn, not the Troll or the Minotaur of course), but also unlikely imo.
We don’t know yet what comes out of the Chaos Wastes DLC regarding enemies, we’ll just have to wait and see.