Go with GRML-medium (128mb ram) with fluxbox
or hag Linux
or my ThorsHammer with grml-magix
run them all without the "toram" option
tinycore can have fluxbox, openbox, jwm, and more
grml-2009 600+mb has like 8 wm's all small
dsl-4.4.10 comes with both jwm and fluxbox
to get fluxbox use bootcode desktop=fluxbox
any of those would run good