Funny timing that you mention Kickstarter now; it just saw some crazy records, with its first couple of million-dollar projects getting funded within a day of each other. And one of them happened to be a game (by the same folks who made Grim Fandango and Psychonauts). It blew its $400k goal out of the water literally overnight:
http://www.kickstarter.com/projects/...fine-adventure
I wonder whether "a Grigori supplement" might be kind of narrow to bring all the dormant In Nomine fans (and would-be fans) out of the woodwork, though. That game project mentioned above wasn't just pitched as "another game by these guys you like," but promoted as basically an attempt to save an entire dying genre, the point-and-click adventure game. In the case of In Nomine, I wonder if you'd see more interest drummed up for a second edition. Then again, considering how some gamers react with hostility to finding out the game they know is declared obsolete, you might get even more traction with a "deluxe edition boxed set" that included revised editions of the core rules and players guides, plus a complete, easily-browsed list of every Resource in the game, including expanded Superiors attunements....
But now I'm just brainstorming because I don't want to go to bed, and I spend a LOT of time thinking about how to market things to geeky niche audiences. (No offense intended to any not-geeks out there who somehow managed to find their way this deep into a gaming community's forums.)