I think it depends on the content. If it was a digital print of a painting, I would have a problem, or if it is a canvas print of a unique image created in digital format, I have no problem with it.
We showed Audrey Bernstein's work at the gallery on canvas, if I remember correctly, they are mixed media works, printed digital on canvas, and then painted on top, and they looked tremendous in the space and in context with the show.
http://artdc.com/2010/04/05/big-graysons-view/See img_2074 on the moveable walls. I like the fact that with out the frame, the images stand on their own.
I like to see photographs on paper, because that is what I'm used too, but depending on the subject and content, I see nothing wrong with printing on canvas as long as we're not looking like reproductions.
Then again, this starts to sound like the historical argument of weather or not photography is art, which shouldn't be a question at this point.
My question for you would be why canvas? Are you trying to create painterly images? Do you like the textured surface of the cloth? If you're looking for alternative views, you could always print on heavy water color paper, and use magnets to attach your images to the wall if you are going for a with out frames look.
You can find great magnets here:
www.amazingmagnets.com