Edit. 5 to 5 stud conversion spacers I would have thought should be piece of piss.
As for the 4 to 5 conversion spacers for different pcds.
You can bolt a plate to the hub. Then have another plate with the new pcd drilled that then bolts to the main plate via several countersunk bolts in a larger pcd. But this method is expensive. I think some euro guys do it this way