Consider an X-10 type of solution. One switch at the top of the stairs can remotely control another using this type of system. For instance, I had several areas in my lower level. For want of a better description, let's call them A, B and C. Each had its own switch. One switch of the same designation. At the top of the stairs, I had a master switch had 4 button, let's call them A, B, C and all. They could remotely control each zone or the final switch could simultaneously control all three zones.
The cost of this isn't that much, installation is a no-brainer and the better quality switches can even have a light for active or dark. With the remote at the head of the stairs, knowing whether the lights somewhere else are on or off doesn't matter that much, though, since hitting On or Off for a zone or all accomplishes it.
The best source I've found for this type of switch is Smarthome.com
Nonny