There may be an interesting market not only for simulated WWVB but WWV / WWVH if someone absolutely needs to sync from HF. Those HF signals are notoriously unstable in phase, so a locally simulated signal may actually be better.
Here's an example of work on simulating WWVB, not yet in mass production:
https://sites.google.com/site/wayneholder/controlling-time.
He could use a precision frequency source if a precise 60 kHz was absolutely necessary.