For my 4E4 RTS entry, I plan to create some extremely low-poly models of tanks etc (like under 100 or maybe even under 50 polys) since the view will be similar to Command & Conquer. Obviously tanks generally have rotating turrets and I wondered how the 3D modellers here would do this for in-game use? Would the turret be a separate model to the tank, or would you create an animation - a bit of a hack IMO. Thanks for any advice.

I'm assuming that you already have a way to draw animated models, so why don't you just assign a specific bone in the skeleton to the turret and just rotate that to get what direction you need. It might not be that simple, depending on how your animator transforms the vertices.

Wouldn't that mean that where the turret joins the chassis, it gets distorted? Obviously the turret and chassis should behave pretty much as seperate entities, apart from the turret being stuck on the chassis!
I don't yet have an animation system which is why I ask, to see if I require one for this or not.

If you want to keep it simple, just divide the model into the base and the turret.
You could implement a very simple pseudo bones/IK system to position and rotate the turret.

Yeah, I was thinking about this a bit more and agree with that - if I have a chassis 'bone' as the base and a turret 'bone' as a child of this, then if the vertices are only affected by a single 'bone' it will do as I wish.

Correct?

Yep, sounds alright to me. With, I presume, the horizontal plane (relative to the tank's base) as the only direction of freedom.
Good luck with the project. And don't forget to include the ninja's. [lol]