Dave - will post some pics for you on Monday, but here's a few points of info as we wrap up our weekend testing -
TextBlade packs really well in jean pockets, and generally the same common sense rules apply as with phones.
It's much smaller than a phone, so it can even go in the coin pocket. Just as with phones, you want to put it in the front pockets rather than the back. Sitting on a phone is not a good idea, and the same applies here.
The polycarbonate is much stronger, and the walls much thicker than with conventional laptop keytops. They resist breakage of the retainer features quite a bit better than laptop keytops.
The SpaceBlade contains the battery, so it is a rigid body with a drawn stainless steel casing. The battery and steel casing are resin-composited together to get a very strong monoblock structure. There are also two additional steel stampings that increase beam strength, and torsional rigidity. At 4 mm gross height, it's thinner than a phone, so like a phone, you don't want to bend it over an edge. When it's carried in the bundle of all three blades during transport, its further protected. The polycarbonate SpaceBlade cover forms a protective perimeter shock zone around the steel / battery composite, so it survives drop on its corners well.
The keyblades are incredibly light - less than half an ounce each, so they survive drop many times higher than a phone. The polycarbonate KeyBlade base is designed to flex without damage, (you can actually bend them a lot), yet they deliver the lowest profile full travel keyboard around.
The highest stress drop event would be dropping the whole bundle of three blades latched together and in the NanoStand sleeve, with one of the exposed corners striking first. The collective mass of the three blades carries more kinetic energy than a single loose blade, and the battery in the SpaceBlade is the heaviest single component.
Still, the aggregate mass is just 1.5 oz, so it's much lighter than a 6S at 4.5 oz.. The light weight and tougher materials mean that it handily survives events that would totally trash your phone screen. So - much more durable than a typical phone.
If you drop the bundle just right, it's possible to pop one of the keytops, if the frameless corner hits at the required angle. It's actually part of the progressive stress relief design to react that way under shock. But if it pops, now you can just snap the keytop back on and you're good to go.
Ran lots of life cycle and abuse tests, and have some video of that. Will try to post some tidbits in the next few days.
As to your question about a full sheath that covers the total length - we designed and built some of those early on, but we discovered that their extra bulk noticeably affects the benefit proposition of amazingly small and light. So we came up with another way to provide total protection for rough-house handling use cases.
We'll post some pics of that, and it will also be available from first ship if you want to config it in your shipment. Would imagine that you'd probably like to do that.