I happen to be one of those oddballs who has a "Super B" color printer (13 x 19 inch), but I originally bought-up to the "commercial grade" more to get the individual ink cartridges than for the larger format.
Unfortunately(?) once you get used to being able to print the larger sizes you get so it "seems necessary," so when the original printer went down I replaced with another the same size that happened to be available locally. Sadly, though, the new one uses a 3-color cartridge that's so tiny it's hard to finish a full color 13 x 19 without running out of ink. I'm not too well pleased with the new one (HP 9650) but getting the old one (HP CP1700) repaired costs about as much in service/shipping charges as buying a new one.
Of course, with any color printer, the ink costs will exceed the original printer cost within a few reams of paper.