I believe that the outline has been written and Mercedes Lackey has started to write the book. The rumor I heard is that she was having problems and made a trip to Tenn to visit with The Lady to discuss what was being written.

Authors, especially authors that pay the rent with their writing, don't work on just one title. They have several works in progress. If one book isn't working, they turn to another. Mercedes Lackey always has several projects on her "to be done" pile, and is probably writing as fast as she can.

As for being "despreate". Well you really should try some of the other books being written by Norton & Lackey. So if you haven't read the Valdemere series by Lackey, there are 21 books just waiting to be read (is Arrows Flight the first one?)
You can also read Andre Norton's other 120-160 titles.

Here are a few other authors to read while you are waiting. I recommend a visit to the library for many of these.
J.K. Rowlings (Harry Potter) - Andre likes these, what more can I say.
Tamora Pierce, "Emperor Mage" (try the kid Trade paper back books);
Jane Yolen, Dragon Blood+;
Bruce Coville; the Mystery shop books: start with "The Monster’s Ring" or "Aliens ate my homework"
Diana Wynn Jones; anything by her - especially DEEP SECRET
Tanya Huff; SUMMON THE KEEPER
Diane Duane; So You Want to be a Wizard
Jane Curry; harder to find ALL are out of print: but look for "Parsley Sage, Rosemary and Time"
Esther Friesner, Harpy High
Rosemary Edghill, The Sword of Maiden's Tears

I've also got a long list that I wrote down at the Boskone panel that had Coville, Yolen, Friesner, Pierce & the daughter of the writing team of Doyle & McDonald.

Well enough of that flag waving (I'll climb down off of my soap box now.)