Hey Brian,
None that I'm aware of; the large number of registered addresses makes it rather impractical to poll all of them at any sort of reasonable frequency.
I would agree that if we had to scan the entire 44/8, that would be a mess but I think that if we took the encaps file as a start and then scanned those IPs, it wouldn't take long at all. Then it comes down to doing a cross-lookup to associate a given 44.net IP with their public IP or some location field to figure out where these active nodes are roughly.
--David