The lost book thread

Welcome to the lost book thread; if you have a book that you can only vaguely remember, here is the place to spill your guts on such books (metaphorically speaking; I am uncertain on the mods' position on hara-kiri threads :o). Here's mine:
I read it when I was young, in about 1993-4. It reads a little like Laurence Yep and the Chinese Monkey King stories. Monkey himself plays a side role in the story. About midway into the story, a painter (one of the main characters) ex-plores a calligraphy/painting set and tastes the ink stick, praising it as coming from the trees on the banks of the ---- river. With the painting set, the painter creates scenes so realistic they come to life, and he befriends a tiger he painted. A story is told of a cave where several soldiers en-tered, but never returned. Eventually, one char-acter is set up for execution by either a lord or the Emperor, but is rescued, I think with the painter's and tiger's aid. The Emperor is de-scribed as having a "personal equator," and with his feet at the south pole and his head at the north pole. As the male and female protagonist prepare to leave by ship, a litter appears chasing them. The man asks, "how many servants are carrying it?" and the woman replies that there are 12-16. He says, "it's the Emperor." Somehow the Emperor is destroyed and the couple escape, and Monkey, who cannot use a magic wand (a significant factor in the story, by the way), causes wooden roses to drop onto the deck.
There were no illustrations.

(no, not the title)

again.

It's a children's book, written by an English author. It's about a group of children who live in the country who discover a magic stone--that might even be the name of the book, by the way--or a pit of some kind that turns art into life. The thing I remember most about it is a scene in which the children let loose a cheetah or leopard woven into a tapestry into the English countryside.

called "The Radio Imp"? About a magic radio that belonged to poor kids in New York City and how it helped them form a family...