Thanks to Ryan for this tip. The Matrox DualHead2Go can be had for around $200 and turns your VGA or DisplayPort on your laptop into 2 additional screens vs. the standard 2nd screen add on. After nearly a week on Windows 7 x64 with two 20” monitors it’s working great. Make sure you get the newest firmware and drivers/software from the link above, that way it has settings to help you manage windows across three screens.
One tip that held me up at first. The device gets power from USB, but must need more power then a powered USB hub can provide, as it didn’t work properly until I plugged it directly into the laptop USB.