I had a set of Coda cartridge-bearing hubs on a C'dale T2000 a few years back. They used standard-sized bearings (B6000 and B6001) that are available from many sources... I got my replacements from
www.biketoolsetc.com (they are a good source for all sorts of other parts as well). I made a tool to press new bearings into the hub body from a large diameter hardwood dowel. Replacing the bearings was very simple: tap the old ones out with a plastic hammer and my homemade tool, then use the same tool to press the new bearings into place. It only took a few minutes.
I sold the C'dale a couple years ago, so the hubs are gone. However, I have a BOB trailer that uses B6001 sealed cartridge bearings in its hub. The bearings press in just like those in the Coda hubs.
Hope this helps. Have fun.