Hi Allan,
Sorry for the late reply. As you are probably aware, Canon realized new firmware which now supports up to 47.2" long. Since I am not aware of any paper that you can buy to handle this length, the ONLY option is roll paper. So since I was very much wanting to print 47" x 17" on my Pro 1000, I purchased a roll, cut it to 48" and gave it a shot, manually holding and helping feeding the paper into the rear. Worked great!. So now in the future, I have "taken a flyer" and purchased the Epson P800 roll accessory and plan to custom mounted it on a wall directly behind and slightly above the rear of the printer. Of course this would be very quirky and require that I strictly attend every roll paper print job, likely pre-cutting the paper to 47" and just use the roller to hold up the long sheet until the print job was finished. Let you know how this turns out soon, once I get the P800 roll accessory mounted. I know, don't say it, this is probably crazy.