Actually, I would consider using new software. Gentoo excels in the area of customized builds that meet only the needs of the hardware. When I used to build my system, my idea of bloat is anything that required GTK or QT. I installed Evilwm, and Ratpoison works really well too. I would also compile Enlightenment's Engage dock. The dependencies were fairly small. If you need a file browser, there are some that don't need GTK or QT, but I would prefer xterm as a file browser over those graphical versions. You may need to experiment some with the system to see what works for you as opposed to just taking someone's suggestion. Debian distros probably would work since they tend to support older hardware.