This is a model I built around the time I made the Atlas (scroll down). This was a scratchbuilt tank hunter based on a russ chassis.
The only GW part used is the hull sides and the tow chain ends. Quite enjoyable to make.
The initial aim was to make a sleek, low slung destroyer. I made the barrel quite long (made it firing solid ammunition, not laser quaser) and attached it and the mantle quite low down.
Favourite features - GS'd teddy bear (ode to dustbin men everywhere) and the tow style hunter killer proxy. Essentially designed as a remote device with a disposable munition.
I sold this to someone in Australia - so I never painted it. Here's a shot of the bits which are removeable (HK, cupola and aerial).