I got to have a look at a completed one of these yesterday at a model show - Airfix had a stand there where they were previewing some of their upcoming releases. I didn't see any indication of when it will be released, but it looked like a production kit not a pre-production mock up, so I suspect that it will be out sooner rather than later.
First off it was a very impressive size - it is a BIG vehicle, probably substantially bigger than the Imprint version.
The 30mm Rarden looked like it might be a little fragile and might need replacing for clumsy wargamers.
It APPEARS that you get a basic Warrior and then that the additional armour packages can be added on on top of this up to the current bar armour package.