Old topic but the link came up in a Google search today.
Vehicle Import Compatibility (Admissibility) list for vehicles purchased in the United States - Section 5.2 - Motorhomes Class B
According to the current list (Aug/12/2015 Edition) you would not
be able to import a Great West Van or Roadtrek to Canada if newer than 2012.
Current (2015) Winnebago, Airstream, Leisure Travel & Pleasure-Way are on the list
I ran into this issue when looking into purchasing a Bigfoot Class C from an individual in the US. He wanting to sell it and the price looked OK to me but I wouldn't have been permitted to import it
The good news was that I found out before
making the purchase.