I know you told us there are no plans for making new devices in near future, but one of my suggestions would be to consider making Passport waterproof or water resistant device.
It's not a bad idea. But the problem with that is that an already pretty expensive device will become even more expensive if it becomes waterproof.
This probably needs a lot of work in redesign of inside, but even cheaper solutions like waterproof cases for protection would be interesting, and you could sell them separately.
The question is how profitable will it be for the company to produce and brand their own waterproof cases if we can already get cheaper ones elsewhere? I personally wouldn't care about the make of the waterproof case as long as it protects whatever is inside, so I see no reason to go for a more expensive Foundation branded waterproof case.