Postworld is a project we have been watching very carefully. Since we originally reported on it, it has moved from a Crysis mod into a stand alone game based on the Unity3d engine. It now looks to be a Fallout inspired game, as opposed to a remake, although the team have stated they wish to deliver a working tech-demo of the game before they make any decisions on the setting. Eye candy:
You can follow the development of this project on the Postworld blog, or the thread here on NMA.