I would think that the Samsonite cases would all be the same and are just modified to accept a trailer. Do you already have the trailer? Wike makes a travel trailer which I have where the trailer part is integrated into the suitcase. About the same price if you were to buy the suitcase and trailer separately but guaranteed that the suitcase will fit the trailer.
Suitcase Bike Trailer | Wike Bicycle Trailers - The Walk and Bike Company