I heard they're a little slow sometimes for high end gaming, but I suspect they could handle a few bar charts, has anyone tried these for trading?
http://www.displaylink.com/products.html
http://www.lge.com/products/model/detail/l206wu_1_6.jhtml
http://www.displaylink.com/products.html
http://www.lge.com/products/model/detail/l206wu_1_6.jhtml