Very nice, Ben.
His 50 ft needs would be 15 meters though, while yours at 5 meters long-side was the equivalent of about 16 feet, no ?
On a far more modest scale than yours, a hotel inn asked for one from
my 8M Rebel XT, a night shot, for use as a 14-ft wide x 8 ft high wall backdrop (as a sale).
I did a couple of interpolations and made sure the detail was still
tight and then gave it to them so their printers could work with that, and
they said it turned out well. But they also said the printers charged a
lot to do that