A mod that changes the base tank to some sort of bipedal Assault Bot, I've always wondered if this would work, but it seems no one has done unit model changes for Vanilla yet.
It would, but bots are a real hastle to make. XP Edit: however it'd have to be more than just the model, unless the model was made veeeery carefully to still work with all the tank bones.
Bot have to have legs, and I don't think it's possible to make movig legs with tank model bones, and without changing json. If I wont be lazy, I can make this, using model from ModX.
What I mean to say is as long as the aim bones are the same you can change it without requiring a server mod afaik.