It would require a complete design project. At this stage there are no plans to do this project.
I suggest you take the Rapido coach car and fill-in the necessary windows to make the Cafe Car. A re work of the interior would need to be done to convert it into the Cafe configuration.
Con-Cor and Kato make reasonable stand-ins, until Rapido come to the game.
If you are talking about "The Canadian" train rolling stock, there are reasonable stand-ins for the silver streamliner cars. The dome cars are a thought, and are on the list of possibles. The VIA Rail Blue cars are available from Rapido Trains