The W3C just released a bunch of bidi- and i18n-related HTML+CSS testcases. The tests and their findings are available at the URL above. Not sure who should own this or how to break it into smaller bugs; CCing hyatt and maciej in hopes they'll know how to triage.
Perhaps, to begin with, we have to go through test results and see which one we're marked as failing and determine which of them we really need to pass (some of them we don't want to pass - e.g. eot support. ).