I got mine from Sweedspeed in NL a few years ago. They're not cheap (aka "eye-wateringly expensive") and are currently showing as 'out of stock' (see https://sweedspeed.com/product/wheelnut-football-rim/ ), but it might be worth giving them a bell if you're stuck.
___________________________ Saab - beyond the conventional !
If you do find someone to make them - let me know - the JP 'Cromodoro' alloy bolt is quite similar to the soccerball bolt and it would be good to have spares or even a complete new set.
I was going to post on here that I'd seen a complete set for sale on Tradera - but that might have been over Christmas as I can't find them now.