I've also just got the chalice left...
Revisited all spots, and I'm at a loss :(
Afraid to close the game, because I don't know if it'll store my progress :D
but WOW it's one of the sweetest little things I've played in a while :):):)
Yeah, the chalice is the hardest object to find, because it was thrown in as an optional extra and isn't really signposted. I should probably update with a clue or two.
But as a hint, the chalice is in the possession of Lord Pixby-Bitsington, an egotistical renegade cat lord, and founder of Meowich. He's currently hiding from the Dread Sorceress, but where would he hide?
Ok, well it's only of use to new players, but I added a clue to a dialog - basically the same hints that I gave above, hopefully enough to put people on the right track.
(And no, it won't save progress - I don't think Bitsy can do that (yet!))