My dad prints a lot of schematics and diagrams on 11x17 to mark up and edit for his job, but color laserjets that can handle 11x17 don't seem to exist outside of the humongous office printers with 5 1000-sheet paper drawers. Probably because the toner cartridges need to be bigger.

He's got a Brother ink tank inkjet, though, which is pretty much the next best thing.