Somewhere down the road, I think it would be very awesome to be able to craft spyglasses (or binoculars, or whatever). They should require a fairly robust material list (I leave it up to Nyx to decide what is fair).
The purpose of a spyglass would be to allow travelers to have a similar application as a Watchtower in a town. Specifically, those who have a spyglass could look at adjacent tiles and see any people present on those tiles.
I could see this being very useful for traders, bandits, and hermits, but should be time or ingredient heavy to keep them semi-rare.
(Sorry, first suggestion, apologies if unclear!)