copying modified files, ignoring size

[Ian Burrell]

How hard would it be to add an option that caused rsync to only look at
the timestamp when copying files? The --size-only causes rsync to skip
files that just have the same size. I am looking for an option that skip
files if the timestamps are the same, but the sizes could be different.
We got a system that results in slightly different files on different
machines but keeps the timestamps the same. We want to update those
files only when they change on the master server.

 - Ian