ikiwiki+openwrt

opkg install git
opkg install perl
opkg install uhttpd
/etc/init.d/uhttpd start

TODO:

install required perl packages
document how to install on USB key with extroot overlay filesystem (http://wiki.openwrt.org/doc/howto/extroot)

Remember that ikiwiki can be setup to just sync HTML files and have the perl/git/etc setup on a separate server. So you could just need a webserver, see plugins/rsync/.