Some time ago I managed to pick up an IBM Thinkpad A21p for $200. I was motivated to make the purchase because it has a 1600x1200 15" display, which if you do the math is 133 ppi, an extremely high-resolution display. The display ended up having some lines down the side (display or flexible circuit problem) but all in all the system works quite well. I've since spent another $120 or so adding 256MB RAM (up to 384MB) and the 3Com MiniPCI combo ethernet/modem. The modem will likely never work in Linux, so I also have a Xircom two-slot-height cardbus ethernet/modem card which is supported.
This is a fairly sweet little system for its time, although it's nothing special now. It's got a Mobile Pentium 3 which runs at about 850 MHz and will step down to 700 or so, and really amazingly crap speakers. And the biggest problem? ATI Rage Mobility M3. The display does not properly report resolutions via DDC (Windows manages to figure it out, but that's not saying much since it's special-cased up the yin-yang) and so you get a horribly mangled display.