Hi Russ
I will try to clarify my point, imagine a car that can have either a Mono or a Spaceframe chassis. Also imagine your paying for labour by the hour. In the UK that could be up to £80 an hour for a body shop.
Lets even make the Mono more expensive to manufacture, even though I am not specifically talkng about a GT40 and most car manufactures know there math but build Monocoque structures.
Now unless you are "Robocop" I cant imagine you could cut and rivet the ally stuff in and replace the chassis quicker than just replacing the chassis alone, so the time for panelleing up must be accounted for somewhere. If you DIY then fine, if its a commercial decision based on overall cost, not sure.
So paying for a damaged mono to be replaced I still dont think would be far off from replacing a damaged spaceframe.
On manufacturing costs, I actually build a spaceframe car , so far in the UK its not been a matter of cost its been finding someone able to subcontract this type of metal work too, figures have varied from £3000 to £5000 for each chassis, it is admit a bit complex with lots of triangulation but it seems to be getting harder to get this stuff done, the material cost is only £400.
Maybe I need a guy like you over here Russ........rockonsmile but make sure you bring all your Robocop attachments also how much electricity do you use theres a bit of a green thing going on over here at the moment.