wheel clamp for alignment

I don't know, seems to me you could fab one as accurate as they make. I would much prefer spindle mount to wheel mount, you then eliminate wheel runout

Since I had alloy wheels and will again, this is a problem. I've even thought about a special nut to replace the spindle but while aligning.......either take a spare nut and braze a piece to that, then turn it true, or use some stock and thread to the spindle thread. This would give you an extended hub to mount the gauge.

(Mine is an old Ammco magnetic)