Thanks.
That turned out easier than I anticipated. I was expecting to have to try to replicate based on specifications (spindle OD, bearing ID, etc). I removed a sample bearing and cleaned it up. In the process I was able to identify the bearing by both manufacturer (Timken) and a part number. The rest was just pounding away on the browser until I found the best search terms to find replacements.
Timken (I believe) has continued to make good stuff.