Hi Kevin, I've been offering gallery wraps on most my landscape work for years and have never had a complaint nor client decide afterwards to have one framed. I feel the gallery wrap helps add another dimension to the image that a flat matted image behind glass doesn't.
While I do all my own work (printing on a Epson 9900 and wrapping) I believe Bay Photo
can help you get what you're looking for.
Regarding post-processing, you'll process the image much the same you would paper however when it comes time to stretch you need to add to the image to take into account the stretcher width. This is easy. Say you have a 30x20 image. What I do is bump the image up to say 30.15x20.12 then enlarge the canvas size by 4" (2" all the way around) giving a finished size of 34.15x24.15. Add a mirror effect on the new canvas area which will serve as the side border. Print the image, protect it then stretch it on the stretcher bars.
You'll need a printer capable of printing on canvas or just have Bay Photo do it for you.
Regarding stretching: There's basically 2-ways, the old wooden stretcher bars (Dick Blick
or Michaels) or take a look at Breathing Colors
as they are offering a newer, easier method of gallery wraps of not only traditional canvas but paper as well. I use the old wood stretcher method and like it. A good friend of mine Ken Doo
in Carmel has been using the Breathing Color method with success.
Either way you go a well done gallery wrap is a piece of art.