Joe, I think there was a 1/20ish R/C "toy" XJ awhile back...can't remember the brand offhand. It was supposedly a pretty accurate body, if we could get ahold of one of those and "shrink" it for resin casting...
Briz, I borrowed your pic of this odd-scale XJ, hope you don't mind...it's the only image on the net that I could find of the 'lil one!