Here is a patchset i made. Its for a clean tor-0.2.2.13-alpha. It excludes all ExcludeNodes/ExcludeExitNodes from a path.
There are lots of log_warn, thes are important to get a clean picture what circs are build.
read the remarks and changenotes at the beginning. At the end are some log-warn that shows the full path..
and this comment line is wrong, all crics with n-hops are handled corretly. // not solved is the n-hop circ list, where n > 3.