Athearn has made them in the past.
You might be able to find one or 2 out there. They might not have decoders but it should be easy enough to add them. If you find an old dead one you might be able to put the shell on a current run unit with sound.
http://www.athearn.com/Search/Default.aspx?SearchTerm=SD60+RTR&CatID=THLD&RN=SOO
Springfield PA