16 monitors... 2 rows x 8 monitors sideway. LOL! How useful can they be if you need to walk up to the monitor on the far top left or top right to view the text display? You can read the 1/4 inch text detail from 4 feet away. Right! (Better grad your cordless keyboard and mouse with you. Yeah right) Unless you can bring these monitors around you in a circle.
2x30" lcd is more than enuff for trading imo. no need to have millions on charts that extend beyond your peripheral vision.
No more than 1440x900. 22-23 inch screens are a good option, being either 1680x1050 or 1920x1050. I wouldn't want 4 charts on less than 1680x1050, but I suppose it depends on what you keep on the charts.