I stumbled across this eBay listing this morning, and I send it along in case it might be of interest:
STUNNING MANUSCRIPT FROM THE LATE 18TH CENTURY,THE COMPLETE ART OF FUGE,185 PAGES BOUND IN NEAR PERFECT CONDITION.THE MANUSCRIPT WAS PROBABLY USED FOR THE FIRST ZURICH EDITION OF THE ART OF FUGE FROM THE EARLY 1800.THIS MOST VALUEBLE MANUSCRIPT WILL BE ON SALE HERE FOR ONE TIME ONLY, BEFORE GOING TO A MAGOR AUCTION HOUSE. GOOD LUCK
Click here: eBay: BACH Johann Sebastian manuscript (item 320032475230 end time Oct-03-06 10:56:20 PDT)
http://cgi.ebay.com/BACH-Johann-Sebastian-manuscript_W0QQitemZ320032475230QQihZ011QQcategoryZ29223QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
The Face Of Bach
"Those in charge are odd and ambivalent towards music, which means I have to live with almost non-stop vexation, envy, and persecution."
Johann Sebastian Bach, October 28, 1730