Specifically, I have an VGA LCD with about a 20" ribbon cable from the ISA controller to the LCD and a pair of leads for the backlight. Can I extend these, oh say, about 10 feet or will there be problems?
This is not easy to do. I have the same problem with my LCD. Because of electrical reasons you cant extand this very far, maybe 1-2 feet. If you want to go 10 feet, you can try making a custom cable (make sure its very shielded) and pray that works. I did this and had noise lines all over my screen. Or you can purchase boards with LVDS (Low Voltage Differential Signaling) technology. One company makes Ultra Link. I believe its very expensive though. Im probably just gonna sell my lcd on ebay, and get an active matrix lcd screen with a normal vga connector.
Good luck