In the U.S. is a catalog supply house called McMaster/Carr.If you give them inside/outside/width dimension they will get ANY bearing you need for very cheap money.When I worked for a plating company in Massachusetts,the circulator pump bearings would get eaten by the various solutions they were immersed in.These bearings,very similar in size to the ones you speak of,came in a tube of 8.Also choice of needle or roller bearings.Do some investigating with an inside/outside micrometer and give them a call.Or,I'll send you a nice vintage Gretsch Floating Action if you send me a nice Premier 252.....