I have the two ACK books in PDF format. The PDFs are enough to make me want to run a game, but I don’t want to do that without physical copies. A search online has yielded nothing. Is there a plan to reprint the core book anytime soon?
The last I heard from Game Salute we had 300 copies left, which are unlikely to have all sold. I sent an email to look into it. The wise thing to do after that hardcover run is up would be to do a second POD printing, but we haven't decided.
Game Salute says that they froze the orders on their stock of hardcovers in order to make sure they had enough to fulfill orders on the Player's Companion backer rewards. I don't think this will be an issue and they should go on sale again at GS within the next week, but it couldn't hurt to write to firstname.lastname@example.org asking them to put one on hold for you and contact you as soon as they're available to order again.