A company which markets assorted
PDA cases and accessories. Rhino Skin is known for its
titanium cases for
Palm organizers. These have had various product names, but most people know them as "Rhinoskins". They are really pretty indestructable, though they add significantly to the Palm's bulk (or lack thereof)-- the package still fits in a (pant) pocket.
This is a pretty good tradeoff-- you weren't honestly planning to carry your PDA in your shirt pocket, were you?