We have something like that now, by the way: buildbot.net/buildbot/...
Seems challenging to get started It could use some good howto documents for getting going. How about something that starts with a small python program, puts it in svn, and setups a buildbot system all on localhost?
NSS and PAM modules for name lookups using LDAP.
An 'ls' showing MP3 metadata.
We have something like that now, by the way: buildbot.net/buildbot/...