This operation can also be done for RAID, so I think that this task should be for Volume Groups in general instead of only for LVM.

In the case of mdadm, you can rename arrays calling this command:

mdadm --assemble /dev/md/alpha --name=alpha --update=name /dev/sdX

Where "/dev/md/alpha" will be changed for the desired device node, "--name" parameter should be followed by the device name (alpha in the example) and /dev/sdX should be changed for the physical device list.

Yeah, then it should be defined for VolumeGroupDevice in the GUI and LVM VG, RAID devices should implement their methods...

One important detail that I forget to mention is that mdadm.conf will need to be updated.