Sure have. Mauser Werke recommends this German Cy. for discontinued spare parts :

Gustav Jehn GmbH, Postfach 1827, 59528 Lippstadt, Tel: 0294129090, Fax: 02941-23418, E-Mail: gustav@jehn.de
http://www.jehn.de/index_e.html

If the barrel you want is in inventory, this would be the fastest way.

However I happen to know that the actual barrel maker is :
http://www.henneberger.de/

And he can make one to order (NB: a friend of mine also has a '66 in .243 and he's ordered a 9,3x62 bbl.)