The attached test case displays only a single background image after <http://trac.webkit.org/changeset/63653>. Prior to that the live rendering in the test case matched the expected reference rendering.
Created attachment 63649 [details]
WORKSFORME now in Safari 5.0.2 (6533.18.5) and nightly r68242 on Mac OS X 10.6 - the live rendering and the expected are identical.
Right, r63653 was rolled out via bug 43592.