Sailfish TOH sounds interesting, but I didn't catch the Jolla's bandwagon yet. Doesn't help that only one of Sailfish devices is TOH-compatible. Wish at least PuzzlePhone included TOH-compatibilty somehow, in its Spine maybe? Yotaphone's dual-screen is a fascinating design, too, but it would have been nicer to have eInk TOH for TOH-compatible phone, instead of being stuck with one fixed hardware design.
Raspberry Pi is too troublesome to make a case for. That's a common problem with users: they don't want to craft a plastic (or wooden) case for a device.