Few more details about the release schedule and supplements for the 40k RPG emerging from the GAMA Trade Show posted here. Seems that in the 18 month gap (!) between the release of the three main games, we can expect 4-6 supplements and some web material. That comes out to four years before we'll see the release of the final core game book (apparently dealing with the elite marines of the Deathwatch unit), with between 10 and 14 books in publication before the last core game hits the shelves.
The schedule presents some interesting problems in itself. While older gamers and fans of the Inquisitor game will probably be most interested by the Inquisitor-type and Rogue Trader games, younger games and new players will most likely be drawn primarily to the opportunity to play a Space Marine, and will not be too happy with the early games if there aren't opportunities along these lines introduced in the first couple of games. BI must be pretty confident that the enthusiasm for a 40k RPG will overcome the 'wait and see' tendencies of gamers that realize that there is quite a bit of cash that will have to be put forth to pick up books in each line. I'm also wondering how they will handle the three core books; putting all the core rules in each book would optimize people being able to focus just on the game that they're most interested in, but would involve duplicating a lot of material and irritating players who want to try out more than one game. On the other hand, taking the d20 "the D&D Player's Handbook is required to play this game about telekinetic ninjas in a futuristic dystopia" approach could elicit some groans from folks who don't want to lay out the cash for, say, Dark Heresy just so they can play Rogue Trader.
It will be interesting to see how it plays out, and we can look forward to a full year of speculation and rumors in the meantime.