I'm wondering if it's possible to modify a hub piloted wheel which is now much more common and available than stud piloted. Assuming the stud diameter and bolt circle are the same, could the stud holes be champhered and the hub bore resized?
I don't think there is.
Stud piloted wheels are mostly SAE (inch) and Hub piloted are mostly Metric.
You may be able to go to your local bearing and wheel place and see if there is a hub that will interchange with your spindle. Or you could go deeper and see if there is a Kingpin/spindle setup that will interchange close enough to make work.
Good luck, no matter what you do.
Also, if you find changeovers, let us know!