If the distance is 7.125 inches, the keyboard is 95 percent, and 6.75 inches is 90 percent. Real notebooks have real displays. You really want XGA resolution, or 1,024 by 768 pixels. There's typically a video-out and a USB port, but you may need the separate expansion bar if you want to connect parallel, serial, or possibly an external drive. Larger notebooks have two PC Card slots, and they're starting to add two USB connectors.
Real notebooks have two drives.
An internal CD drive weighs less than 10 ounces and an external drive weighs about a pound. You can leave them at home. Real notebooks have real batteries. Your battery life suffers. On some but certainly not all ultraportables, battery life is down to under 2 hours.