Try the Bilibo, a hard shell of molded plastic that can be a hat, a bucket, a stool or a sit-and-spin.
If you routinely carry a lot of loose papers and files, it's best to buy a hard shell briefcase.
LeatherBriefcases.com offers a great selection of all types of leather briefcases of in both soft and hard shell.
You find dual cases that includes a hard shell clam cases for your prescription glasses and a soft pocket that attaches via Velcro on the inside, just for your clip-ons.
They can keep your clip ons from getting lost or broken by protecting them as a pouch within a larger case or as a smaller, hard shell case that stands alone.