I like LexJet Sunset Select Satin Canvas for photo printing and art-reproduction for eco-solvent printers. The lustrous, satin surface of this canvas supports a high level of quality for both photo murals and large-scale art reproductions, even at the higher output speeds.
http://www.lexjet.com/p-3387-lexjet-sunset-select-satin-canvas-suv.aspx
I build my own gallery wrap frames by cutting down 1x4's on a table saw, it's not a big deal and I can make any size I need. My finished frame is 3/4" x 1-1/4" which gives a nice wrapped effect, but not over bearing. The one part to remember is to bevel the edge of the frame about 3° that goes towards the front, so the edge does not telegraph (show) on the front of the finished wrap (see drawing below). I
After running the 1x4 through the table saw and making the frame profile as shown in the drawing below, I miter cut the pieces as you would a picture frame, put a dab on wood glue on the joints, and secure with a small brad nailer.
After the frame is complete, I stretch the canvas over the frame and secure on the back with 1/2" staples, add a small "D" ring for a mounting wire and it's done.