The image above is the layout I'm most happy with. I have extended the construction bay and removed a pillar. The room itself is now deeper.
I have decided to scale down the most recent chop-shop rectangular layout so that only one construction bay is present within the interior. The portion of the room to the left of the red marquee line on the drawing above will be removed.
I have been looking at various reference material to begin to establish the actual appearance of the interior. The concept piece will be more detailed and complex in design to the final 3D model due to poly count/ memory. Plus my 3D modelling capabilities are limited.