ABANDONED
With the addition of the Respawn Anchor in 20w12a, this mod is now superfluous.
ObsidianSpawn
This mod allows you to set your spawn-point in any dimension using Crying Obsidian.
I created this mod because I think there should be a way to set your spawn-point in the Nether, and Crying Obsidian seemed the perfect block to do it.
This mod currently supports the 1.16 snapshots.