I don't recall much of a survival aspect to Inuyasha; I can only really see fighting and rpg/action-adventure games made from it.

I have thought about making a Trigun fangame before, but it's no where near worth the effort. A open-world RPG shooter where you make money based on bounties and decent story ark. Concept I thought of would be where each player starts and is thrown into a town, instructed by a NPC to cary out a 'bounty' on a chicken and gives you a gun, to which after you complete the task; you're thrown into the MMO portion of the game, where you're free to explore the world and do quest as you please. Player created bounties and task to complete, PvP duels and such. I near drooled over the thought of being able to play a game such as so.