I have had a Canon ipf6100 24" printer for about a year and a half now and find it excellent. If you need to make big prints, 24" is the way to go. The Canon has worked flawlessly for me, and it does get quite a lot of use. Many of my prints are small, but as I have to print a lot, I tile them up in Lightroom templates and print them on the roll paper. Sometimes I can get through a 30m roll of paper in a few days. Which is my only concern, as you are doing much lower volume. How will the ink stand up to long term storage in the printer? Since Feb 08, I have changed the Grey cart 11 times, the Photo Grey cart 4 times, and the Blue and Photo Cyan only once. That probably covers about 18 30-metre rolls, plus hundreds of A4 and A3 sheets.
At you volume, the lesser used cartridges could be in place for the lifetime of the printer!
The printer is big, and very heavy. But I have mine in the office on what is basically a kitchen work-top that is 24" deep. When in use I open the drawer under the work-top, and slide a couple of long pieces of old mount-card beneath the printer to catch the paper as it emerges. This setup negates the need to use the separate printer stand and paper catcher.