I needed a depth-limited, filtered search of a directory tree recently and came up with the following wrapper around os.walk that brings in a few niceties like glob-style filtering, depth limiting and symlink traversal that is safe from infinite loops. It also emits a named tuple rather than the bare tuple emitted by os.walk:

http://code.activestate.com/recipes/577913-selective-directory-walking/

I think this would make a nice addition to 3.3 as shutil.filter_walk, but it need tests, documentation and reformatting as a patch before it can go anywhere.