OS X Server has an option to host a Time Machine share, and it's doable without OS X server, just a little more manual. You can stash the share anywhere on the machine, included RAID disks if you wanted.

Machines backing up to it will be creating a sparseimage. As long as they aren't encrypted, or you are okay with keeping the password on the server, you can then mount those sparse images and pull the data from the /latest . Issue is, when the sparseimage is mounted to mirror to glacier, clients may get errors. Including possibly a dialog that would wipe the sparseimage and start over.

You could possibly mount it in the middle of the night, mirror it locally, then sync that mirror to glacier. Still could cause some errors on Macs due to time machine backups attempts during a powernap.

Or possibly host the sparseimages on a volume that allows snapshots, and just mount a snapshot instead.

I've been meaning to do something similar. Until then, I just ended up throwing Backblaze at the situation.