Try Gibson Research Corporation's Wizmo app. It can be configured to do a lot of neat tricks, including powering down monitors. I haven't tried it on my laptop yet so I can't promise it'll work. You can get it here: http://www.grc.com/wizmo/wizmo.htm
Here is an excerpt describing the "Monitor Off" feature:monoff — turns off all monitors
Any system monitors that support Windows advanced power management (APM) will be immediately powered down until they are awakened by the keyboard or mouse movement. Since this is a Wizmo hosted mode, the mouse sensitivity "shake=" command can precede the "monoff" command to set or disable subsequent mouse movement unblanking. Other Wizmo commands to change system settings may be placed before and after the "monoff" command to alter the system's operation while the monitors are powered down.
Example: wizmo monoff
Let me know how it works out. Thanks.