They have not but could possibly do it in the future as they have the Kenefick Business Car in the Fall catalog to go with the Bush Funeral Train. I would love to see them do the Cheyenne as well. I got a private tour of that car back in college when UP Solicitor General out of Houston had the business train in Austin, Texas.
The next best thing would be to find K-Line's 18" Union Pacific Arden Business Car.