I came up with this a week ago, and it works great.
My bike luckily works without one anyway, but if you can't quite get the chain dialed in even with a half link, or just want to make dang sure it never derails, here is your antidote.
I LIKE the 1x1 with vert. dropouts. The axle always goes back in the same spot, and the frame is strong. Unlike my beach cruiser with horizontal dropouts, this frame doesn't feel mushy and it doesn't feel like the wheel is twisting side to side.