Looking for a hard backpack case for my acoustic guitar. Help? [GEAR]

Hi guys. I recently acquired a lovely Rainsong hybrid guitar and it has a great hard case. But, as I'm a music therapist, I'm usually lugging around a LOT of different instruments and it'd be great if I could strap my guitar to my back. I've been looking for a backpack case but they're all soft, gig-bag types and I'd like something with a bit more safety. Any suggestions? Thanks!