Dan,
If I may suggest you try the "SLICK" release of OpenSuse on one of these laptops. It has an optimized boot process as well as other KDE processes to provide a full KDE experience on slower hardware. I have it running on a 500MHz system with decent results considering the resources available. If you have any questions, feel free to contact me.
The SLICK release can be found here: http://en.opensuse.org/SLICK
Best regards, Daniel