Is it possible? IBM Tivoli seems to have devadd command, so it should be possible - any knows what devadd does to achive it?
All the official procedures say to reboot, but just a theory, what happens if you go into the zone root from the global zone and use mknod to manually create the device node? You definitely won't be able to do it inside the zone as one the purposes of a zone is to prevent access to resources not assigned to it. I don't have a tape drive available on a dev system to try it out.