I think I have found the most challenging body to fit on a Dnano chassis.
An AC Cobra

At first glance it won't fit, due to the very short wheelbase, but if I remove the H bar it fits with the rear tires almost touching the chassis block.

More pics
here
Also found an old Heller 1/43 kit. This one fits the Murcielago chassis perfectly. Funny the Sauber Mercedes is also the first body to be released with the new Mini-z chassis MR03...