Beth, I stretch Claessens 13DP linen on 36 x 48" stretchers all the time. Not a problem.

Beth,

How exciting!! Can you email me and tell me who it is? Dior dress, hummmmm. If you don't want to stretch this yourself, why don't you order the canvas from the supplier that Sharon posted on her "Alicia Rose" post. That was a large canvas. It may be difficult for you to stretch a canvas tight enough because of your hands and having to pull with the canvas pliers.
Alicia