I have also been unable to get my Canon i9900 USB printer working. I had assumed it was because there doesn't seem to be a driver for it out of the box, but could be a bug in Cups.
I had no joy with a Canon ip4000 until installing 'gutenprint-cups', restarting CUPS, and picking the gutenprint driver (which actually listed the model - went to the 'admin' tab, and it was listed as a new printer'). Worth a try... Chris
