Hi Again Invert,
Just a wild thought, you may wish to consider a smaller size as well. There are allot of people with small to midsize cars that would not mind having a pond racer if they could just get it to fit. Since it will be in a CAD format, would it be possible to scale down to a size that would make it a reasonable model for the rest of us? Might make enough to pay for the props you will need for the large model ! Hmm maybe even sell a construction article to a popular model magazine. You never know...
Best Wishes and keep us posted