You can replace your display using one left over from an i1200 or i1300, but you have to take into thought many things. On, you will void your warranty, risk breaking your machine, spend a few bucks, and a few hours. On any replacement of the screen, I recomend replacing the panel as a whole instead of taking the panel apart to get the LCD out, as that is hazardous and putting your computer in even more risk. Also, if you want to upgrade our screen from the 12.1" SVGA screen to the 13" XGA screen, you'll need to do a BIOS update before replacing the screen with a BIOS that supports the bigger screen. BIOS updates can be found on IBM's website.
ThinkPad 600X (2646-D3U): 500mhz Pentium III, 320mb RAM, 13.1" XGA, 12gb, Win 2000 Pro SP4
Hewlett Packard 95LX: 5mhz NEC V20, 512kb RAM, MS-DOS 3.2