Doesn't SKF do this? It's been a while, but most bearing companies seemed to have large cross references to their competitor numbers, the better to switch you to their product. I would expect SKF to want to keep the customers they have, so they should at least index their own.
Do you have a part in mind or is this just a what-if question?
Edit to add: Most bearing brokers/resellers will have that same sort of information, assuming it's available. I would not expect custom bearings to be listed.