I was fascinated with the unusual design of the Moties described in the Niven & Pournelle novel The Mote in God's Eye. I don't recall ever seeing any illustration showing a Motie. Have any illustrators made such a thing, published anywhere, and especially prior to around 2000?
There's one by Lee MacLeod on the cover of the 1993 Simon & Schuster / SFBC edition (ISFDB-10: 1-56865-054-X, ISFDB-13: 978-1-56865-054-8), but maybe that's what you meant by "around 2000".
This Pocket Books edition (ISBN-10: 0-671-66054-3, ISBN-13: 978-0-671-66054-3) seems to be earlier; "Cover artwork copyright 1986 by David Eigge" says ISFDB.
Found this on Quora: http://qr.ae/jKNG9 Looks more like a low-poly character for a game rather than a full finely detailed illustration meant to be inspected and enjoyed on a book cover. Still, it's one of the very few examples of a Motie I've come upon since asking this question.
Funny Motie expression on this one:
Amazon and Abebooks say Publisher: Pocket; 1st edition (1974) but ISFDB says that the cover art is copyright 1986 by David Egge. (See the end of Valorum's answer -- I now notice that it looks like Valorum meant to post this picture as well.)
There are actually two entries currently on ISFDB for this ISBN. They spell the artist's last name differently: