I wondered why a sprawling, frontier-based MMO wasn't yet a thing, and sadly I'm still wondering.
Indie company Nesoi Tech apparently shares my affinity for the genre, judging by its new Bone Gulch Kickstarter project. It's a Unity-based sandbox game featuring "an advanced crafting system, a unique bounty system," and "extensive player customization," among other things.
Nesoi's press release also mentions single-player story-based campaigns "in addition to local and online multiplayer action," so we're not quite sure how MMO it is at this point. There's some pre-alpha video footage available, though, and we've embedded it for you after the cut.
[Source: Nesoi press release]