Advice on selecting color laser printer for up to 12"x18" formats

Aloha!
I am currently looking into starting a small online business, part of which requires color laser printing up to 12"x18". I am also hoping to find a printer with finishing options, including saddle-stitching, hole-punching and folding, as well as the ability to handle heavy cardstock. Could someone please provide their advice as to which brands/models are best in terms of print quality and low operating costs? I have been attempting to research this online, and the best I could find (within a $5K or under price range) is the Xerox Phaser 7800. However, it has received mixed reviews due to operating bugs. Can anyone offer an alternative? I would greatly appreciate any advice you have to offer!
Mahalo nui loa!
Sephari