Lee Pennington has been published in more than 300 magazines--and rejected so many thousand times that in one six-month period he papered al four walls of a room with rejection slips. ("I loved getting the 8 by 11 rejections more than the 3 by 5 ones because they covered more space.) He has also filled scrapbooks with rejection slips, used them for coasters, and given rejection parties--invitations written on the back of rejection slips.
[I have received form rejections letters a year after the books in question were published by other publishers.]
Rotten Reviews & Rejections, 1998