I read through them too. I was thinking last night. There are really two options. Re-make proper ones like HemiMark did or modify the spindles and calipers to accept a metric version. There are standard bolts easily available here but one would need to fiddle around a bit. It's probably the quickest solution. Using standard bolts is probably not a very good idea, to be honest. There will be a clearance between bolt and caliper and the way the thread sits 1/4" in the hole of the spindle, the bolt will be subjected to large bending and shearing forces.