Lens for 40x40"

A friend of mine is dreaming up a van camera and wants to get a 40x40 paper negative out of the beast. I have no idea what the options are for lenses that would cover big enough but if anyone has a suggestion, please let me know.

The Van:

surplus shed sells very large diameter plano convex lenses.
they cover a very large area ( have nice fall off too )
you might figure out what focal length you might need and go
to their website they have a TON of stuff, and are helpful on the phone too

will the bumper sticker say" if this van's a rockin' im processing paper negatives!" ?

john

How about a pinhole to start?